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Biological colonization and biodeterioration of architectural ceramic materials: An overview
Abstract
This work presents the first review on biodiversity, biodeterioration and bioreceptivity of architectural ceramics. Literature dating from 1972 to 2014 was compiled and analysed in order to summarise the current knowledge and to facilitate a better understanding of the subject. Data regarding biodiversity found on architectural ceramic materials was described for three typologies: bricks, roofing tiles and glazed wall tiles. A vast biodiversity has been identified on these ceramic materials, from bacteria to more complex organisms, such as plants. Bricks were the most studied substrate, while literature on glazed wall tiles was scarce. The highest biodiversity was found on bricks, may be due to the fact that this was the most studied typology. Several works regarding the colonization of ceramic roofing tiles by lichens were found in the literature, which led us to realise that this is a topic that arouses the attention of several researchers. Photoautotrophic microorganisms found on glaze wall tiles represented a considerable biodiversity in this ceramic typology, with many genera in common with those identified on bricks and roofing tiles. Nevertheless, in the searched literature, different methods had been used to identify and characterize the organisms. This made the comparison of the global biodiversity found on these substrates difficult. Architectural ceramic materials exposed to outdoor conditions are often affected by biodeterioration. This worldwide problem can cause aesthetical, physical and chemical damages on ceramic materials. The distinct biodeterioration processes occurring on the different substrates found on architectural ceramic materials are explained in detail. The relationship between the ceramic intrinsic properties and bioreceptivity was discussed. Porosity and surface roughness seemed to play a major role in bioreceptivity to colonization. Ceramic microstructure has a strong influence on the resistance to biodeterioration. Finally, the authors come to the conclusion that there are many gaps in the knowledge, especially concerning glazed ceramics, and thus, further research was proposed.
... However, other local environmental factors may influence facade microbial colonization, possibly contributing to some differences in microbiota community composition between the stains in sites B, M or Z. For example, the proximity of the site B to the Monsanto Forest may influence the microbial community diversity due to dispersal of airborne particles possibly containing organic substrates and microorganisms from the surrounding soil and diverse vegetation (Coutinho et al., 2013(Coutinho et al., , 2015Savković et al., 2021). On the other hand, two heavily congested urban freeways also in the proximity of site B can be a source of pollutants (e.g., SO x , NO x , CO, hydrocarbons, etc.) possibly contributing to surface anomalies like darkish runoff marks (Amaro et al., 2014) and increased bio-receptivity Parracha et al., 2021b). ...
... The main microbial phototrophs found in the ETICS facade stains (e. g., cyanobacteria mostly of the genus Chroococcidiopsis/family Xenococcaceae, and Chlorophyta green microalgae) have been reported as biodeterioration agents frequently found in building exteriors (Gaylarde and Gaylarde, 2005;Crispim et al., 2006;Coutinho et al., 2015;Ferrari et al., 2015;Komar et al., 2022;Wu et al., 2022). In terms of biodeterioration potential, their darkish, bluish, greenish, or brownish pigmentation may contribute to the color/aesthetic anomalies (Gaylarde and Gaylarde, 2005;Shirakawa et al., 2011;Ferrari et al., 2015). ...
... On what concerns heterotrophic bacteria as colonizers and potential biodeterioration agents in the ETICS facades, many of the alphaproteobacteria (e.g., families Rhodobactereaceae, Acetobactereaceae, and Sphingomonadaceae), actinobacteria (e.g., Kineosporiaceae, Pseudonocardiaceae, and Frankiaceae), bacteroidetes (e.g., Cytophagaceae) and Deinococcus-Thermus taxa (e.g., Truepera) found prevalent in the ETICS stains' microbiota, have been also detected in biofilms of other building surfaces (Gaylarde and Gaylarde 2005;Coutinho et al., 2013Coutinho et al., , 2015Rosado et al., 2020;Wang et al., 2022). These bacteria are generally ubiquitous in nature (soil, water, and plants) and can undergo airborne dispersal by sticking to dust particles, ultimately ending up on surfaces where they can establish and grow (Gaylarde and Gaylarde, 2005;Denner et al., 2006;Karlsson et al., 2020). ...
External Thermal Insulation Composite Systems (ETICS) are frequently used to enhance the energy efficiency of the built environment. However, stains of presumable biological nature are often detected shortly after application , causing cladding defacement and altering the building aesthetics. To address which microbiota could contribute to these biodeterioration related color/aesthetic anomalies, samples collected from stains detected on the surface of building facades with ETICS in three residential sites in Lisbon, Portugal, were analyzed through microbiological culture-dependent technique and culture-independent amplicon DNA high throughput sequencing taxonomic profiling. The obtained data provided a comprehensive description of microbial communities assigned to diverse taxa of the major microbial groups of heterotrophic bacteria, fungi, cyanobacteria, and microalgae (through DNA plastid detection) in the sampled stains. Based on that, we propose that new microorganisms could be added to the list of bio-susceptibility testing organisms in ETICS. Furthermore, microbiota diversity depended more on facade location and cardinal orientation than on ETICS material composition. Overall, this study reveals the unique microbial communities of color/aesthetic biodeterioration stains in ETICS facades, unlike those of other surfaces, and the associated environmental dynamics.
... Lesser investigations are available on ceramic objects although they are an important part of the worldwide cultural heritage (Pena-Poza et al., 2018;Quagliarini et al., 2019;Guiamet et al., 2019;review in Fomina and Skorochod, 2020). Bioreceptivity of ceramics mainly relates to physical characteristics such as porosity and surface roughness (Gazulla et al., 2011;Coutinho et al., 2015). In vitro tests performed inoculating microbial communities, isolated from outdoor artworks, on ceramic roofing tiles demonstrated that these substrates are highly bioreceptive to microbial colonization (Laiz et al., 2006). ...
... Porosity has been indicated as a crucial factor driving the bioreceptivity of ceramic materials, because of its influence on the absorption and movement of water, and thus on the water availability for microorganisms (Coutinho et al., 2015). In this work, different ceramic objects exhibited different porosity values that relate to i) production processes, ii) chemical and mineralogical composition of the raw materials, iii) the firing conditions and iv) environmental and microbial weathering (Tschegg, 2009) (see Sections 3.3 and 4.1). ...
... The detection of lichens and microbial communities on the examined objects reflects the well-known high bioreceptivity of stone substrates located outdoors, and in particular of ceramics (Coutinho et al., 2015). Most lichen species colonizing the dolia and the sculptures are common constituents of lichen communities on siliceous stone heritage surfaces, which often share xerophytism and photophytism -related to direct sun irradiation-and nitrophytism -related to the location in green areas (Nimis et al., 1992). ...
Although ceramic objects are an important part of the worldwide cultural heritage, few investigations on the effects of lithobiontic growth on their outdoor conservation are available in the literature. Many aspects of the interaction between lithobionts and stones are still unknown or strongly debated, as in the case of equilibria between biodeterioration and bioprotection. This paper describes research on the colonization by lithobionts on outdoor ceramic Roman dolia and contemporary sculptures of the International Museum of Ceramics, Faenza (Italy). Accordingly, the study i) characterized the mineralogical composition and petrographic structure of the artworks, ii) performed porosimetric measurements, iii) identified lichen and microbial diversity, iv) elucidated the interaction of the lithobionts with the substrates. Moreover, v) the measurements of variability in stone surface hardness and in water absorption of colonized and uncolonized areas were collected to assess damaging and/or protective effects by the lithobionts. The investigation showed how the biological colonization depends on physical properties of the substrates as well on climatic conditions of environments in which the ceramic artworks are located. The results indicated that lichens Protoparmeliopsis muralis and Lecanora campestris may have a bioprotective effect on ceramics with high total porosity and pores with very small diameters, as they poorly penetrate the substrate, do not negatively affect surface hardness and are able to reduce the amount of absorbed water limiting the water ingress. By contrast, Verrucaria nigrescens, here widely found in association with rock-dwelling fungi, deeply penetrate terracotta causing substrate disaggregation, with negative consequences on surface hardness and water absorption. Accordingly, a careful evaluation of the negative and positive effects of lichens must be carried out before deciding their removal. Regarding biofilms, their barrier efficacy is related to their thickness and composition. Even if thin, they can impact negatively on substrates enhancing the water absorption in comparison to uncolonized parts.
... Biofilms that grow on building materials are initially invisible but turn visible with time, as their development leads to thick and pigmented structures. Finally, the last step of biodeterioration implicates the colonization of such a mature biofilm by mosses or higher plants, especially on stones (Coutinho et al., 2015;Gulotta et al., 2018;Li et al., 2018;Q. Li et al., 2016;Norma Italiana UNI 11182, 2006). ...
... According to the building materials industry, the first problem with microbial colonization is its unsightly aspect (Coutinho et al., 2015;Di Martino, 2016). Indeed, the biofilm that develops on the materials is often pigmented, which forms unaesthetic dark or green streaks or spots (Di Martino, 2016), which is undesirable since customers expect their product to stay stable over time (The Brick Industry Association, 2018). ...
... Therefore, manufacturers of building materials invest massively in strategies to prevent their products to rapidly turn green or black, and building owners face significant expenses to clean and restore materials that have deteriorated over time. Thus, in addition to the unsightly appearance, biodeterioration causes less visible but more significant damages, including the modification or loss of physical properties of many types of materials (Coutinho et al., 2015). Indeed, as the biofilm grows, surface and deep cracks increasing the porosity of materials are observed (Berdahl et al., 2008;Coutinho et al., 2015). ...
All types of building materials are rapidly colonized by microorganisms, initially through an invisible and then later a visible biofilm that leads to their biodeterioration. Over centuries, this natural phenomenon has been managed using mechanical procedures, oils, or even wax. In modern history, many treatments such as high-pressure cleaners, biocides (mainly isothiazolinones and quaternary ammonium compounds) are commercially available, as well as preventive ones, such as the use of water-repellent coatings in the fabrication process. While all these cleaning techniques offer excellent cost-benefit ratios, their limitations are numerous. Indeed, building materials are often quickly recolonized after application, and microorganisms are increasingly reported as resistant to chemical treatments. Furthermore, many antifouling compounds are ecotoxic, harmful to human health and the environment, and new regulations tend to limit their use and constrain their commercialization. The current state-of-the-art highlights an urgent need to develop innovative antifouling strategies and the widespread use of safe and eco-friendly solutions to biodeterioration. Interestingly, innovative approaches and compounds have recently been identified, including the use of photocatalysts or natural compounds such as essential oils or quorum sensing inhibitors. Most of these solutions developed in laboratory settings appear very promising, although their efficiency and ecotoxicological features remain to be further tested before being widely marketed. This review highlights the complexity of choosing the adequate antifouling compounds when fighting biodeterioration and proposes developing case-to-case innovative strategies to raise this challenge, relying on integrative and multidisciplinary approaches.
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... Ceramic roof tiles are traditional and widespread building components covering up to 74% of French roofs (Fédération Française des Tuiles et Briques, 2019). As other construction materials (i.e., bricks, stones, cement, or concrete), clay tiles face extreme environmental conditions, such as wide temperature variations, rain, wind, or frost (Coutinho et al., 2015;Saiz-Jimenez, 2001;Warscheid and Braams, 2000), that can weather them. However, tiles also undergo biodeterioration, a natural phenomenon caused by microbial colonization (Guiamet et al., 2013;Warscheid and Braams, 2000). ...
... Initially invisible, the biofilms become pigmented over time. At an advanced stage of maturation, they support the settlement of mosses and plants (Coutinho et al., 2015;Gulotta et al., 2018;Li et al., 2018;Rossi et al., 2012), the final colonizers of the mature microbial biofilm development. ...
... Among these final colonizers, bryophytes (i.e., Bryum argentum or Tortula muralis), plants (i.e., Bromus hordeaceus or Sedum sediforme), and lichens (i.e., Endocarpon pusillum or Verrucaria nigrescens) were identified (Coutinho et al., 2015). The settlement of these macro-organisms on building materials requires a succession of colonizing episodes by a wide variety of microscopic microorganisms, including bacteria, algae, and fungi (Barberousse et al., 2006;Coutinho et al., 2015;Fassier, 2009;Ortega-Calvo et al., 1995;Romani et al., 2019;Warscheid and Braams, 2000). ...
Like other building materials, ceramic roof tiles are biodeteriorated over time. Natural conditions affect deterioration processes, but the development of a biofilm composed of many types of microorganisms also plays a critical role in biodeterioration. However, the pioneering stages of biofilm formation remain poorly studied, whereas they determine the development of the well-characterized mature biofilms. To further characterize this pioneering microbial diversity, the bacterial, algal, and fungal colonization of new tiles exposed to outdoor conditions over one full year was monitored, combining fluorimetry, biofilm imaging (SEM, confocal macroscopy), culture-based, and high-throughput sequencing approaches. For all the samples, pioneering biofilms were found to be extremely diverse but dominated by Actinobacteria (Pantoea sp. - up to 90% of the bacterial diversity -, and Pseudomonas sp. -up to 75%-), Chlorophyta (Trebouxiophyceae -100% of the algal diversity-), and Pleosporales (Alternaria sp. -up to 75% of the fungal diversity-). Interestingly, if biofilm development was highly heterogeneous between tiles and exposition sites, microbial colonization patterns succession remained comparable regardless of tile type and exposure site. Additionally, we investigated whether microbial isolates collected in this study harbor some physiological traits related to their pioneer character. This work revealed that pioneer organisms colonizing tiles harbored interesting features like the ability to produce biofilm matrix and anti-quorum sensing and antimicrobial compounds, highlighting the intense competition between the microbial players during the priming of the tile colonization. Altogether, our results emphasize the necessity to taxonomically and functionally characterize the key pioneering microorganisms involved in biofilm formation to design innovative antifouling solutions for ceramic roof tiles.
... Fungi are highly versatile, ubiquitous, chemoheterotrophic microorganisms, being able to grow in a vast number of materials and contributing to the development of various biodeterioration phenomena [2,3]. Such modifications are a result from fungal species settling, development and exploitation of various organic and inorganic compounds present in historic art-pieces and monuments [2][3][4][5][6][7][8][9][10][11][12][13][14][15]. The fungal biodeterioration of books, paper, parchment, textiles, photographs, paintings, sculptures and wooden materials occurs due to the aesthetic modifications, mechanical pressure and exoenzymatic action [2]. ...
... Another example of microorganism's attack of organic materials is related to the biodeterioration of human remains, mummies and funerary materials, where opportunistic, saprotrophic and highly cellulolytic and proteolytic taxa are able to thrive and trough their actions severely alter them [2,14,15]. Complementarily, historic relics mainly composed of inorganic components such as stone, frescoes, glass and ceramics can also suffer deep aesthetical, physical and chemical modifications resulting from fungal grow and action [2][3][4][5][6]12,16]. In these supports, deterioration is caused by hyphae penetration into the substrate, the production and release of extracellular destructive organic acids, enzymes and metabolites and by the the formation of distinct colored outlines as a result of fungi high pigment contents, contribution to biofilm development and chemical reactions with inorganic compounds [2][3][4][5][6]. ...
... 2021, 11, x FOR PEER REVIEW 2 of 37 them [2,14,15]. Complementarily, historic relics mainly composed of inorganic components such as stone, frescoes, glass and ceramics can also suffer deep aesthetical, physical and chemical modifications resulting from fungal grow and action [2][3][4][5][6]12,16]. In these supports, deterioration is caused by hyphae penetration into the substrate, the production and release of extracellular destructive organic acids, enzymes and metabolites and by the the formation of distinct colored outlines as a result of fungi high pigment contents, contribution to biofilm development and chemical reactions with inorganic compounds [2][3][4][5][6]. ...
Fungi are known to contribute to the development of drastic biodeterioration of historical and valuable cultural heritage materials. Understandably, studies in this area are increasingly reliant on modern molecular biology techniques due to the enormous benefits they offer. However, classical culture dependent methodologies still offer the advantage of allowing fungal species biodeteriorative profiles to be studied in great detail. Both the essays available and the results concerning distinct fungal species biodeteriorative profiles obtained by amended plate essays, remain scattered and in need of a deep summarization. As such, the present work attempts to provide an overview of available options for this profiling, while also providing a summary of currently known fungal species putative biodeteriorative abilities solely obtained by the appli-cation of these methodologies. Consequently, this work also provides a series of checklists that can be helpful to microbiologists, restorers and conservation workers when attempting to safeguard cultural heritage materials worldwide from biodeterioration.
... Indeed, the presence of pores promotes liquid water absorption, which is essential for microbial development [5,6] and favors the penetration of microorganisms into the material. Bacteria, algae, and fungi thus settle on tiles, forming multispecies biofilms embedded in a thick protective matrix that they synthesize [4,5,[7][8][9][10]. Over time, these biofilms become mature and pigmented, producing black or green spots on roofs that are seen by customers as unaesthetic, and microorganism metabolic activities profoundly alter the composition of tiles. ...
... Over time, these biofilms become mature and pigmented, producing black or green spots on roofs that are seen by customers as unaesthetic, and microorganism metabolic activities profoundly alter the composition of tiles. These biofilms also promote the settlement of macroorganisms such as plants and mosses [8,11,12] and ultimately cause significant alterations in tiles. ...
... We exposed ceramic roof tiles coated with these two distinct types of water-repellent compounds for over six years and then combined SEM, EDS analysis, and confocal macroscopy to characterize the extent of multispecies biofilm colonization. In addition, in vitro assays were carried out to evaluate the effectiveness of these two common water repellents in slowing down the growth of two eukaryotic ceramic roof tile colonizers: Cladosporium cladosporioides, a widespread melanized fungus [19,20], and Stichococcus bacillaris, a common lichenizing green alga [8,21,22]. ...
Ceramic roof tiles are widespread marketed building materials, rapidly colonized by microorganisms that form multispecies biofilms on their surface and play crucial roles in biodeterioration processes. Coating tiles with water repellents is a pervasive industrial strategy employed to prevent liquid water penetration and slow biodeterioration. Very few studies have examined the links between the characteristics of water-repellent coatings and biofilm colonization patterns. Our work aims to compare the effects of coating tiles with two common water repellents (siliconate and siloxane) on the growth of colonizing microbes. We combined in situ exposure of tiles for over six years and macroscopic and microscopic observations with in vitro biotests, relying on the use of algal and fungal models. Our data showed that (1) tiles coated with water repellents were macroscopically less colonized by lichens (2) a significant fungal biofilm development at the microscopic scale (3) water repellents had very contrasting effects on our model strains. These data reinforce the great interest for industry to conduct more studies linking the nature of the water repellents with the composition of colonizing multispecies biofilms. The long-term objective is to improve the available water repellents and better adapt their selection to the nature of microbial colonization.
... The range of environments colonized by microbes is not limited to the surface but extends deep underground to over 5 km [51] and reaches extreme environments which, until recently, were thought to be inhabitable [52]. Microorganisms are abundant and interact with mineral matter in biofilms and microbial mats associated with ponds, hot springs, marine sediments and sub-seafloor basalts, on the rocks and minerals in cold and hot deserts, dust, as well as in anthropogenic environments including mine drainage areas, mineral-based building materials, constructions and monuments [24,25,[53][54][55]. For example, it is estimated that~75% of the greatly colonized submarine basaltic glass in the upper 300 m of the ocean crust is being altered through microbially induced weathering which is several orders of magnitude faster than inorganic alteration [13]. ...
... Human extensive use of clays can lead to modifications of the natural environment and the changes in the ecological diversity, creating the additional settings for microbe-clay minerals interactions. The illite, kaolinite, chlorite, vermiculite or smectites have been traditionally used in manufacturing ceramic building materials, e.g., bricks, roofing and wall tiles, since antiquity [54]. The porous and rough surfaces of such materials can readily harbour various microorganisms facilitating their attachment and biofilm formation. ...
... The porous and rough surfaces of such materials can readily harbour various microorganisms facilitating their attachment and biofilm formation. The microbial colonization of the ceramic surfaces exposed to light is reported to start usually with the establishment of the communities of phototrophic microorganisms (cyanobacteria and microalgae) and their symbiotic associations with fungi (lichens) followed by a successive colonization by bacteria and fungi and, finally, plants [54]. According to the currently available data, the overall biodiversity of ceramic-dwelling microorganisms includes 70 bacterial taxa, 97 cyanobacteria, 65 algae, 49 fungi and 9 lichens. ...
Clay minerals are very common in nature and highly reactive minerals which are typical products of the weathering of the most abundant silicate minerals on the planet. Over recent decades there has been growing appreciation that the prime involvement of clay minerals in the geochemical cycling of elements and pedosphere genesis should take into account the biogeochemical activity of microorganisms. Microbial intimate interaction with clay minerals, that has taken place on Earth's surface in a geological timescale , represents a complex co-evolving system which is challenging to comprehend because of fragmented information and requires coordinated efforts from both clay scientists and microbiologists. This review covers some important aspects of the interactions of clay minerals with microorganisms at the different levels of complexity, starting from organic molecules, individual and aggregated microbial cells, fungal and bacterial symbioses with photosynthetic organisms, pedosphere, up to environmental and biotechnological implications. The review attempts to systematize our current general understanding of the processes of biogeochemical transformation of clay minerals by microorganisms. This paper also highlights some microbiological and biotechnological perspectives of the practical application of clay minerals-microbes interactions not only in microbial bioremediation and biodegradation of pollutants but also in areas related to agronomy and human and animal health.
... Members of these classes colonize anthropogenic glass (Mellor 1924;Weaver et al. In review); natural and anthropogenic architectural and sculptural stone (Coutinho et al. 2015;Reblova et al. 2016); and sandstone, quartzite, granite, and limestone tombstones (Brewer and Fierer 2018). Under natural settings, members of these classes form microbial communities on polar desert rocks (Choe et al. 2018) and other endolithic environments (Gorbushina 2007;Pokharel et al. 2017;Staley et al. 1982), including the subsurface (Sohlberg et al. 2015). ...
... Sandstone and quartzite (Chen et al. 2000;Choe et al. 2018;Coleine et al. 2018). Architectural stone (Coutinho et al. 2015). Ultramafic and non-ultramafic rocks (Rajakaruna et al. 2012). ...
... (16S) glasses and Fe-free glass (Perez et al. 2016). Architectural ceramic materials (Coutinho et al. 2015). ...
... There is also evidence in the literature showing that rock, mineralbased materials (Gadd and Dyer, 2017;Gadd, 2017;Gaylarde and Baptista-Neto, 2021), and stones (Richardson et al., 2014) are also rapidly colonised by microorganisms because of the presence of crevices, fissures and pores on their surfaces, which allow microbes to grow and penetrate their pores. Other building materials reported to have suffered microbial invasion include plastics (R€ aty et al., 1994), paints (Shirakawa et al., 2002), glass (Stanaszek-Tomal, 2020) and ceramics (Coutinho et al., 2015). Regarding the comparative susceptibility of different building materials to microbial decay, findings from the existing studies vary. ...
... (2015) that the susceptibility of buildings of different façade materials to microbial colonisation depends on the availability of organic matter on their façade materials rather than their classifications into various types. However, the emergence of the buildings with ceramic tiles as their predominant façade finishes as the least susceptible to microbial decay in this research can be explained based on the compactness and smoothness of façade finishes made of ceramic tiles, which according to Coutinho et al. (2015), do not allow anchorage by microbes and decline adsorption of moisture by ensuring easy run-off of rainwater splashes. Similarly, the findings on the susceptibility of buildings with façade finishes of bricks and ceramic tiles seem to resonate with that by Simons et al. (2018) and Fagbeme et al. (2018) indicating that buildings finished or cladded with earth-based materials that had undergone heat treatment were less prone to fungal colonisation. ...
Purpose
Buildings respond differently to microbial invasion depending on the design, type of construction materials and finishes used and extent of exposure to climatic factors. However, in the hot-humid tropical environment of Nigeria, much is not known about how buildings with different types of façade finishes or claddings are liable to microbial decay. The purpose of this research is to investigate the susceptibility of buildings with different types of façade finishes to microbial decay in Enugu metropolis, southeast Nigeria.
Design/methodology/approach
A survey involving physical observation of purposively selected 383 buildings and questionnaire administration to their owners was carried out in the study area. The data were subjected to descriptive and logistic regression analyses.
Findings
Most of the 383 buildings sampled were less than 41 year and 47% of them had painted façade finishes followed by 25.1% with cementitious finishes. Around 63.4% of the buildings had their façade finishes or claddings colonised by microbes. Older buildings of 15 years and above and those with cementitious materials and paints as their predominant façade finishes were more likely to experience microbial decay than newer ones and those having refractory bricks, ceramic tiles, aluminium composite materials and plastics/polymers as their predominant façade finishes or claddings.
Practical implications
The study identifies the categories of buildings that are likely to be more susceptible to microbial decay; and thus contributes to research on how to slow down the rate of biodeterioration of building façade finishes or claddings in the hot-humid tropical environments.
Originality/value
This is the first study on the susceptibility of buildings with different types of façade finishes or claddings to microbial decay in the hot-humid tropical environment of Enugu metropolis, southeast Nigeria. It also provides a clue on the age at which buildings become more vulnerable to microbial decay in the study area.
... All mineral building materials, including cultural heritage objectives, are subjected to microbial colonisation, which can determine their long-term biodeterioration [1,2]. This phenomenon consists of aesthetic damage, together with the loss of structural integrity and alteration of physical and chemical properties of many types of materials [3,4]. Controlling the biodeterioration of cultural heritage is becoming a major challenge, due to its heterogeneous nature dependent on biodeteriogen types and their degree of extension, as well as the artefact conservation status and environmental factors [5]. ...
... To confirm the stability of the other compounds (2)(3)(4), and the result obtained with cavoxin, a quantitative analysis was carried out using HPLC. Standard samples of compounds 1-4 were used to obtain HPLC calibration curves (Table 1) for their quantitative determination in ISO medium solutions after 72 h. ...
Biocides based on chemical synthetic compounds have been commonly used to counteract damages caused by microorganisms on stone cultural heritage. However, in the last few years, the use of commercial and traditional biocides has been banned and/or limited due to their dangerous profile for the environment, as well as human and animal health. Natural products could be used as suitable alternatives for cultural heritage purposes, as they have low toxicity and stability compared with synthetic pesticides. Even if most of the investigated solutions have already shown promising results, their efficiency, ecotoxicological, and chemical features are poorly investigated. In this manuscript, we aimed to evaluate the ecotoxicological profile of four fungal metabolites—namely, cavoxin, epi-epoformin, seiridin, and sphaeropsidone—with potential antimicrobial properties for monumental artworks. A battery of ecotoxicological tests using Aliivibrio fischeri (bacterium), Raphidocelis subcapitata (alga), Raphanus sativus L. (macrophyte), Daphnia magna (crustacean), and Caenorhabditis elegans (nematode) revealed a relative lower toxicity of these compounds, especially when compared with Preventol® and Rocima®, commercial biocides mainly used for the conservation of cultural heritage.
... However, their preservation on-site raises concerns regarding their conservation, since glasses are particularly sensitive to environmental degradation, and are also very vulnerable to biodeterioration [8][9][10]. Microbial colonisation is a major problem of these building materials due to the damaging consequences of biodeterioration [10,11]. For decades, research has focused on the characterisation of biological communities based on the taxonomic identification of colonising organisms [12]. ...
... Lichens have been studied on stained glass [48], but not recently. On both glazed roofing tiles and glazed tiles, lichens have been reported [11]. However, only glazed roofing tiles have been more extensively studied [49,50]. ...
The main goal of this work was to review the 21st century literature (2000 to 2021) regarding the biological colonisation and biodeterioration of glass-based historical building materials, particularly stained glass and glazed tiles. One of the main objectives of this work was to list and systematize the glass-colonising microorganisms identified on stained glass and glazed tiles. Biodiversity data indicate that fungi and bacteria are the main colonisers of stained-glass windows. Glazed tiles are mainly colonised by microalgae and cyanobacteria. Several studies have identified microorganisms on stained glass, but fewer studies have been published concerning glazed tiles. The analysis of colonised samples is a vital mechanism to understand biodeterioration, particularly for identifying the colonising organisms and deterioration patterns on real samples. However, the complexity of the analysis of materials with high biodiversity makes it very hard to determine which microorganism is responsible for the biodeteriogenic action. The authors compared deterioration patterns described in case studies with laboratory-based colonisation experiments, showing that many deterioration patterns and corrosion products are similar. A working group should develop guidelines or standards for laboratory experiments on fungi, bacteria, cyanobacteria, and algae on stained glass and glazed tiles.
... Complex microbial communities composed of bacteria, fungi, algae and cyanobacteria, have been identified on glazed tiles [3,5,7,8,10,11]. Aesthetical disfiguration is a conspicuous consequence of microbial growth [5,9,10,12]. Researchers have also reported other injurious effects, such as physical decay caused by the penetration of microorganisms emphasized that the substrate properties, particularly high roughness and porosity, also influence the treatment's efficacy [50,51]. ...
... One of the advantages of the TiO 2 applied as coatings is the immobilization of the nanoparticles on the surface, avoiding their penetration and reducing leaching. The impact of nanoparticles on the environment following leaching from treated surfaces is an actual concern due to the lack of ecotoxicity data [12]. The aging of coatings and consequent loss of their properties are also a major concern that has been described in several works [52,53]. ...
Historical glazed wall tiles are a unique vehicle of artistic expression that can be found outdoors, integrating the buildings of many countries, therefore they are often subjected to biodeterioration. In this work, the applicability of protective coatings on glazed tiles to prevent biological colonization was evaluated. Thin films of titanium dioxide (TiO 2) obtained by sol-gel were applied on glazed tiles to appraise its anti-biofouling properties and to evaluate their suitability for cultural heritage application. The TiO 2 coating was tested on four different Portuguese glazed tiles and a modern tile. The chemical and mineralogical characterization of the glaze and ceramic body of the tiles was examined by wavelength dispersive X-ray fluorescence spectroscopy (WDXRF) and X-ray diffraction (XRD). The produced TiO 2 coating was chemically and morphologically characterized by micro Raman spectroscopy (µ-Raman) and field emission scanning electron microscopy (FESEM). The anti-biofouling properties of the TiO 2 treatment were evaluated by inoculating the fungus Cladosporium sp. on the glazed tiles. Potential chromatic and mineralogical alterations induced by the treatment were assessed by color measurements and XRD. The TiO 2 coating did not prevent fungal growth and caused aesthetical alterations on the glazed tiles. A critical analysis evidenced that the tested coating was not suitable for cultural heritage application and highlighted the challenges of developing protective coatings for glazed tiles.
... The various forms of stone degradation are due to physical, chemical, and biological phenomena linked to factors such as changes in temperature, solar light, and wind incidence, permeation of water containing organic and inorganic substances, biological attacks, salts crystallization, mechanical stress, and other effects [1][2][3][4]. Therefore, knowledge of the history and location of each monument is extremely important for the evaluation of its state, specifically related to synergistic actions of environmental factors, past and present, such as internal erosion due to biological colonies previously settled and already extinct in porous stones [5][6][7][8][9]. ...
We report on the XPS analysis of degraded surfaces inside San Pietro Barisano, the rupestrian church carved into the calcarenite rock of ancient Matera, which has been a UNESCO World Heritage Site since 1993. As reported in previous works, the “Sassi” district and the park of rupestrian churches were available as open laboratories for the National Smart Cities SCN_00520 research project dedicated to the sustainable recovery of this remarkable architectural heritage. In that context, XPS functionality was shown to reside in the possibility of analyzing surfaces by feasible sampling, acquiring spectra without any preliminary sample treatment, and processing data using a well-established curve fitting procedure. The obtained results allowed us to identify the degradation products of the investigated surfaces, thus contributing to defining a diagnostic framework for subsequent actions. Accordingly, the samples here considered, collected from the internal wall surfaces of the church, were all analyzed in comparison with the reference calcarenite, and the XPS results were evaluated as a function of local environmental factors and the historical context of the church itself. The final aim was to provide, for each sample, the most representative indicator(s) of biotic and/or abiotic degradation for reliable use, in a multidisciplinary context, in planning care interventions for building heritage.
... Like stones, the identified biodiversity in earthenware materials is extensive, ranging from microorganisms to plants. It encompasses bacteria, cyanobacteria, algae, lichens, mosses and fungi, having their peculiar biochemical and physical properties [4,5]. Moreover, the composition and properties, such as surface texture, granulometry, porosity, and water sorption, are crucial factors in determining the bioreceptivity of ceramics. ...
In recent years, there has been a growing interest in exploring environmentally friendly and healthy alternatives to conventional solvent cleaning and biocides in the conservation of stone artworks. Here, we focus on the potential of laser-based photonic methods for treating biodeteriorated earthenware artefacts. The investigation was conducted on Roman dolia (jars) of the International Museum of Ceramics, Faenza, Italy. Three removal methods were tested and compared: (i) brushing using a soft-bristled electric brush and water, referred to as brush cleaning; (ii) a combination of brushing and laser ablation; and (iii) biocide and brushing. Four laser systems with different wavelengths and optimized pulse durations in nanosecond or microsecond regimes were used in the tests. Systematic irradiation tests were conducted to determine the damage thresholds and define safe laser irradiation levels. The characterizations of the surfaces under treatment were carried out pre- and post-laser irradiation using optical microscopy, 3D photogrammetry, and Pulse-Amplitude-Modulated Chlorophyll-Fluorometry. Furthermore, spectroscopic methods based on FTIR, Raman, and LIBS techniques were used to assess the effectiveness of the removal process and the composition of uncovered surfaces. Results have indicated that gentle brushing and water is the most effective approach for safely removing around 60% of the bio-colonization weakly anchored to the substrate over the area under treatment. This comprised viable species, whereas the remaining 40% of the area included endolithic species, mostly thalli of Verrucaria nigrescens and rock-dwelling fungi. The eradication of the latter was the real conservation concern requiring attention. Following the experimentation, the optimal method for safely uncovering the earthenware surface was a combination of water-assisted brushing and 1064 nm laser irradiation as a finishing treatment.
... In addition to cassiterite, the presence of marcasite was also noted in the glazes of samples Nos. 1, 2, and 7. The formation of this mineral is associated with the biological deterioration of cobalt dyes by bacteria [47]. This type of defect in archaeological ceramics with high-lead glazes is also called as blackening ( Figure 11). ...
... The rough surface concentrates moisture in micro-cracks or pores. They are usually where the greatest growth of microorganisms occurs [20]. Moisture comes from atmospheric conditions, but primarily from the metabolic activity of microorganisms. ...
Biodeterioration may take place due to the influence of microorganisms, leading to the deterioration or destruction of materials. This process involves distinct mechanisms of material breakdown, such as mechanical damage, decomposition, corrosion induced by microorganisms, and fouling caused by living organisms. Research and literature data on biological corrosion of polymer-modified cement materials (polycarboxylate resin) are ambiguous and even contradictory. Samples, 20x20x160 mm in size, made of cement-polymer mortar with 5% polycarboxylate resin were prepared for the test, with 6 specimens for each determination. The study determined the level of contamination of the material, using the culture method and COD, after 18 months of exposure to Penicillium and Cladosporium fungi. In addition to this, bulk moisture content, water absorption, flexural strength and internal structure were determined using a scanning microscope and EDS analysis was carried out. The beneficial role of polymers has been demonstrated, e.g. by sealing the structure of cement-polymer materials. However, there is also an increased development of biocorrosion associated with organic material as a food source, especially for molds that colonize materials in favorable conditions. The test results showed that there was a strong growth of mold fungi on the material and the mass humidity was high. However, the strength increased slightly, and after further exposure to a corrosive environment it decreased again.
... Physical fungal deterioration can occur by expansion of the hyphae throughout the construction material leading to mechanical alterations [11]. That is, as the fungal biofilm grows, shallow and deep cracks are observed that increase the porosity of the materials [7,12]. Furthermore, this increased porosity facilitates the colonization of the materials by other microorganisms and promotes their growth. ...
Biodeterioration of building materials causes financial losses as restoration and conservation processes need to be carried out. Filamentous fungi invade the surface of ceramic materials causing fungal deterioration, in these cases, coatings with antimicrobial additives are used to control this phenomenon. This research is aimed to assess the use of sol-gel coating with antifungal nanoparticles to control biodeterioration on ceramic materials. Nanoparticles were obtained by green synthesis using an aqueous solution of tannin from Schinopsis balansae and Caesalpinia spinose. Moreover, AgNO 3 salt, 3-aminopropyltriethoxysilane (AMEO), or 3-mercaptopropyltrime-thoxysilane (MTMO) were used as precursors on the sol-gel coatings. Coatings with AMEO and silver nano-particles showed better antifungal performance to protect ceramic materials, as opposed to those coatings containing MTMO and silver nanoparticles. Therefore, the functionalized sol-gel coatings with antifungal nanoparticles showed their efficiency in the control of fungal deterioration to protect clay bricks.
... The traditional porcelain ceramic tile is a costeffective building material derived from minerals that has been widely applied to numerous fields such as architecture, electronic panels, and protective armor. 3,4 However, the inherent brittleness of traditional ceramic tiles limits their applicability because they have negligible plasticity during fracture due to relatively pinned dislocation, which would cause catastrophic brittle fracture under loads. 5 In this case, the problem of improving both the strength, impact resistance and toughness of traditional ceramic tiles with low costs is recognized, 6,7 and in fact, this is also a huge challenge to achieve in ceramic engineering research. ...
Ceramic materials with high strength, toughness, and excellent impact resistance are urgently required for many structural applications, but these mechanical properties are difficult to achieve in traditional ceramic tiles due to their inherent brittleness. Inspired by the specific structure of shells, the multilayered ceramic tile/Kevlar fabric composite with a bio‐inspired shell structure was successfully fabricated via a surface hydroxylation followed by simple hot press process. It is found that the composites have representative step‐like fracture behaviors rather than brittle fracture, which has been proven to possess a better ability of mechanical performance and noncatastrophic failure behavior compared to same‐thickness ceramic tile. Specifically, the bending strength, fracture toughness, and fracture work of the composite with a 15‐tier structure come to 836.5 ± 12.5 MPa, 14.6 ± .2 MPa·m1/2, and 7228.8 ± 108.4 J·m1/2, which are even better than those of reported advanced materials. Such fracture‐resistant behaviors are correspondent to the strengthening effects of the crack deflection, interfacial debonding, and fiber pull out, accompanied by bio‐inspired structure and appropriate bonding state between brittle or ductile layers. This resin or fabric content can be used as well as the slip systems to transfer the internal stress in time to consume more fracture energy per unit length and prevent risky brittle fracture, while carrying loads. We expect these findings to provide vital guidance for promoting the applications of traditional ceramics in bio‐inspired high‐performance composites for actual ceramic manufacturers.
... This biodegradation consists in changing the visual appearance of the materials (spots, discoloration), lixiviation, development of the inability of thermal and hydric isolation or solar reflectance (in the case of ceramic tiles), efflorescence, disintegration of the ceramic matrix, glaze exfoliation, increase of capillary porosity of the ceramic body or chemical alteration (Coutinho et al. 2016). Several methods for identifying microorganisms and biodeterioration factors have been presented in the literature (Coutinho et al. 2015, Ranalli et al. 2019, Romani et al. 2019. ...
... The presence of this minor component can be caused by chemical, biological damage (chemical biodeterioration of transition metal oxides which are represented as colourants in glazes) of the transition metal oxides, which act as colourants in glazes. This type of damage to archaeological ceramics with high-lead glazes is also referred to as blackening caused by sulphur-reducing bacteria [59]. In the white faience glazes applied to a shard with a high proportion of CaO and MgO, the reaction with the underlying shard at the interface preferentially produces calcium silicate-based minerals instead of lead feldspars. ...
Corrosion effects in deposit environments (soil, waste pit, etc.), together with the glaze adherence and fit, could cause severe deterioration accompanied by different types of defects or growth of corrosion products. The aim of this work was to identify the source of surface degradation of the lead-glazed ceramics sets from the Prague area from the Romanesque to the Renaissance period. A combination of X-ray fluorescence (XRF), X-Ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy with energy dispersive X-Ray spectroscopy (SEM/EDS), and simultaneous thermal analysis (STA) techniques along with stress state calculations was used to study the defects. Based on the interpretation of the possible sources of the observed defects, four types of degradation effects were schematically expressed for the archaeological samples. It was shown that the glazes were already appropriately chosen during the production of the Romanesque tiles and that their degradation occurred only due to long-term exposure to unsuitable environmental conditions.
... In this sense, ceramic materials exposed to outdoor conditions are often affected by fungal deterioration. Porosity and surface roughness play a major role in bioreceptivity to colonisation [3]. The use of antifungal functionalised coating with nanoparticles (NPs) to control biodeterioration is being intensively studied [4]. ...
Green chemistry is the preferred approach for the synthesis of metal and metal oxide nanoparticles due to its environmental friendliness, feasibility, and safety to human health when compared with other chemical or physical methods. Caesalpinia spinosa is a promising resource to be applied in the green synthesis of metallic nanoparticles due to the high amount of polyphenols. The aim of the present research was to obtain an antifungal coating functionalised with nanoparticles synthesised from C. spinosa tannin and aqueous solutions of metallic (silver and copper) salts to control biodeterioration of acrylic paints and bricks. Green synthesised NPs were characterised by UV-vis spectroscopy, transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). The silver nanoparticles with average size of 12 nm and obtained from a 500 ppm aqueous solution of C. spinosa tannin inhibited the growth of Aspergillus niger, Penicillium commune and Lasiodiplodia theobromae. These strains were previously isolated from a biodeteriorated facade. Functionalised coating obtained with silver nanoparticles synthesised from C. spinosa tannin is reported for the first time as antifungal protective system of acrylic paints and bricks.
... Thus, isolates that are in the same group can have the same growth and ecological strategies, share the same ecological niches, and use the same substrate. Similarly, Coutinho et al. [41] reported that strains belonging to the Alternaria, Cladosporium, Penicillium and Aspergillus genera were isolated on architectural ceramic material. These last two as primary colonizers of the substrate and r-strategists. ...
Fungal deterioration of building materials causes economic losses due to restoration processes and because it affects the health of the people exposed. Therefore, it is necessary to obtain highly deteriorating fungal strains to carry out studies focused on biodeterioration control. The aim of this research was to study the mycobiota involved in deterioration of facades through the isolation and characterization of fungal strains. In this sense, this paper characterizes the mycobiota that contributes to the deterioration of brick and concrete present in those places. Samples were taken from bricks and concrete with visible biodeterioration of the Cathedral of La Plata and the Experimental Station of the Centro de Investigación y Desarrollo en Tecnología de Pinturas. Relative density, apparition relative frequency, and ecological category of fungi isolates were determined. The deteriorating attributes were determined by carbonate dissolution test, pigment secretion assay, acid production test and brick weight variation. Cladosporium sp., Penicillium sp. and Aspergillus sp. were the taxa with the highest apparition relative frequency and abundance. Aspergillus niger MN371276, Lasiodiplodia theobromae MN371283, Cladosporium sphaerospermum MN371394, Penicillium commune MN371392 and Arthothelium spectabile MT071822 were the strains with the highest biodeteriorant activity. These strains can be used in studies on biodeterioration control of buildings materials.
... Microorganisms, being the most ubiquitous and abundant living organisms on the planet, occur in great numbers in mineral-rich environments, including building stone and other rock and mineral-based materials in the built environment and cultural heritage such as monuments (Gadd 2017;Coutinho et al., 2015;Caneva et al., 2020), museum artifacts and specimens (Pinzari et al., 2019;Piñar et al., 2020). Bioweathering or rock and mineral decay by microorganisms occurs as a result of two synergistic groups of mechanisms: biomechanical and biochemical, where biochemical processes are considered to be much more important than mechanical biodeterioration (Money 2004;Gadd, 2010). ...
Microbial activity following invasion of human-made structures and artifacts can have profound social and economic consequences including the permanent loss of cultural heritage. The unique frescoes in the 11th century Saint Sophia's Cathedral (Kyiv, Ukraine) have recently suffered from dark-spot biodeterioration. The aim of this work was to elucidate the microbial nature of biodeterioration and the biogeochemical processes occurring in the areas of the dark spots. Culture-independent approaches including scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), micro-X-ray diffraction and real-time quantitative polymerase chain reaction (qPCR) analysis were used in this study. SEM and qPCR data demonstrated that the main agents of fresco biodeterioration were mycelial fungi, with bacteria unlikely to play a major role in the development of the dark spots. SEM-EDS results showed that fungi colonization of the dark spotted areas resulted in mechanical and chemical weathering involving dissolution of mineral components of the plaster (mainly calcite) and displacement of mineral grains, which compromise the stability of the plaster or fresco. SEM-EDS also detected fungal biomineralization of secondary mycogenic minerals: calcium malate, hydrated aluminium and ferric phosphates. Biomineralization of calcium malate by fungi, as found in this study, is a rare biogeochemical phenomenon, possibly linked to the presence of calcite and nitrogen limitation.
... Kerusakan komponen bangunan dapat disebabkan oleh beberapa faktor antara lain korosi biologis [1] maupun faktor masa pakai bangunan atau degradasi [2]. Upaya untuk mengatasi kerusakan komponen bangunan diperlukan pemeliharaan bangunan [3] dengan melakukan perbaikan atau penggantian komponen bangunan yang akan menentukan besaran biaya pemeliharaan bangunan. ...
[ID] Di kota besar seperti Palembang terdapat beberapa bangunan mall yang telah berusia belasan tahun dan mengalami kerusakan arsitektur. Salah satu faktor penyebab kerusakan dikarenakan masa pakai bangunan atau yang disebut dengan degradasi. Untuk mengembalikan kondisi bangunan ke keadaan semula dan memperpanjang umur bangunan, diperlukan pemeliharaan dengan melakukan perbaikan atau penggantian komponen bangunan. Pemeliharan bangunan memerlukan biaya yang terencana. Hal yang menjadi fokus penelitian ini adalah pemeliharaan preventif dan corrective. Tujuan penelitian ini adalah menghitung estimasi besaran biaya pemeliharaan bangunan untuk 10 tahun mendatang. Metode Composite Condition Index digunakan untuk menghitung besar tingkat kerusakan bangunan. Penggantian komponen bangunan dilakukan dengan memprediksi kondisi komponen bangunan, sedangkan estimasi biaya pemeliharaan menggunakan metode analisis nilai masa depan. Analisis data menggunakan data kuantitatif dengan variabel penelitian adalah semua biaya pemeliharaan. Hasil perhitungan menunjukkan nilai Indeks Kondisi Bangunan untuk komponen arsitektur bangunan mall adalah 76,24% yang berarti ada 23,76% kerusakan bangunan. Kerusakan terbesar terjadi pada area koridor yaitu sebesar 25,47% dengan Indeks Kondisi Bangunan sebesar 74,53%. Biaya pemeliharaan tertinggi terjadi pada tahun ke-7 sebesar USD 580,854. Biaya ini meningkat 5,8 kali lipat dibandingkan tahun pertama, dengan penggantian material komponen terbesar untuk komponen lantai dan pengecatan dinding. [EN] In a big city like Palembang, several mall buildings are a dozen years old and have architectural damage. One factor that causes damage is the life of the building or what is called degradation. Maintenance is required to restore the condition of the building to its original state and extend its life. Maintenance is done by repairing or replacing building components. Building maintenance requires planned costs. This research focuses on preventive and corrective maintenance. This study aims to calculate the estimated cost of building maintenance for the next ten years. We used the Composite Condition Index method to calculate the level of damage to the building. Replacement of building components was done by predicting the condition while estimating maintenance costs using the future value analysis method. Data analysis using quantitative data with research variables are all maintenance costs. The calculation results show the Building Condition Index value for the architectural component of the mall building is 76.24%, which means there is 23.76% building damage. The most significant damage occurred in the corridor area, 25.47%, with 74.53% a Building Condition Index. The highest maintenance costs happened in the 7th year of USD 580,854. Compared to the first year, this cost increased 5.8 times, with the most extensive component material replacement for flooring and wall painting components.
... Starting from discoloration, biodeterioration may end up causing high maintenance and repair costs for the external surfaces of constructions, monuments, outdoor furniture and so on, even leading to hazards to human health (e.g. slipping problems when it occurs on pathways) [9,11,12]. Among these microorganisms, microalgae growth is one of the less investigated phenomena to the authors' knowledge, especially compared to mould and fungi. ...
A correct assessment of microalgae growth on porous building materials (i.e.: fired bricks, sandstones and limestones) can provide a useful tool for researchers and practitioners. In fact, it may help predicting the biofouling damage extension and it can assist the experts in a correct planning of maintenance interventions to limit costs. The literature regarding such issue outlined the Avrami’s model as the most recurrent one, even considering the influence of biocidal treatments on the substrate. However, it seems to have some limitations when the growth is very fast or, conversely, when the latency time is extended over the time. Therefore, a different modelling approach is here proposed, by using the logistic function (extensively used i.e. in population growth). Results reveal that the logistic function seems to succeed in better modelling the available experimental data. Moreover, it seems to overcome the limits of the Avrami’s model, as well as to be less influenced by the main drivers of microalgae growth, such as porosity and roughness of the substrate, biocides treatments and environmental conditions (temperature).
... Sediments and minerals can support the growth of a variety of microbial communities, and the composition of microbial communities also feedback, influencing the creation of different environmental conditions [45,46]. As seen in Figure 3C, the abundance of archaea was much smaller than that of bacteria. ...
The properties of rocks can be greatly affected by seepage hydrocarbons in petroleum-related mud volcanoes. Among them, the color of sedimentary rocks can reflect the changes of sedimentary environment and weathering history. However, little is known about the microbial communities and their biogeochemical significance in these environments. In this study, contrasting rock samples were collected from the Aiqigou mud volcano on the southern margin of the Junggar Basin in Northwest China as guided by rock colors indicative of redox conditions. The physicochemical properties and mineral composition are similar under the same redox conditions. For example, the content of chlorite, muscovite, quartz, and total carbon were higher, and the total iron was lower under reduced conditions compared with oxidized environments. High-throughput sequencing of 16S rRNA gene amplicons revealed that different functional microorganisms may exist under different redox conditions; microbes in oxidized conditions have higher diversity. Statistical analysis and incubation experiments indicated that the microbial community structure is closely related to the content of iron which may be an important factor for color stratification of continental sedimentary rocks in the Aiqigou mud volcano. The interactions between organics and iron-bearing minerals mediated by microorganisms have also been hypothesized.
... In this sense, ceramic materials exposed to outdoor conditions are often affected by fungal deterioration. Porosity and surface roughness play a major role in bioreceptivity to colonisation [3]. The use of antifungal functionalised coating with nanoparticles (NPs) to control biodeterioration is being intensively studied [4]. ...
Green chemistry is the preferred approach for the synthesis of metal and metal oxide nanoparticles due to its environmental friendliness, feasibility, and safety to human health when compared with other chemical or physical methods. Caesalpinia spinosa is a promising resource to be applied in the green synthesis of metallic nanoparticles due to the high amount of polyphenols. The aim of the present research was to obtain an antifungal coating functionalised with nanoparticles synthesised from C. spinosa tannin and aqueous solutions of metallic (silver and copper) salts to control biodeterioration of acrylic paints and bricks. Green synthesised NPs were characterised by UV-vis spectroscopy, transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). The silver nanoparticles with average size of 12 nm and obtained from a 500 ppm aqueous solution of C. spinosa tannin inhibited the growth of Aspergillus niger, Penicillium commune and Lasiodiplodia theobromae. These strains were previously isolated from a biodeteriorated facade. Functionalised coating obtained with silver nanoparticles synthesised from C. spinosa tannin is reported for the first time as antifungal protective system of acrylic paints and bricks.
... Outdoor exposed stone cultural heritage is subject to various types of deterioration. Chemical and physical deterioration, due to the action of the atmospheric agents, is the most evident, but in the last decades the attention of the conservation scientists has been drawn towards the microorganisms which can colonize stone surfaces and cause biodeterioration [1][2][3][4][5]. Although stone surfaces are hostile due to the scarcity of nutrients, sun exposure and available water, and many physical stresses, several microorganisms colonize these niches, often organized as sub-aerial biofilms (SABs) [6]. ...
Due to their ability to penetrate, deteriorate and discolour stone surfaces, rock-inhabiting black fungi represent a remarkable issue for cultural heritage conservation. Black microcolonial fungi (MCF) can also adapt to different environmental conditions, by converting from yeast-like morphology to a peculiar meristematic development with swollen cells (torulose hyphae, TH), to extremely thin structures (filamentous hyphae, FH). Furthermore, black MCF produce protective pigments: melanin, dark pigment particularly evident on light stone surfaces, and carotenoids. Black fungi produce melanin in critical, oligotrophic conditions as well as constitutively. Melanin function is mostly related to stress resistance and the ability of fungi to generate appressorial turgor to actively penetrate plant cells in pathogenic species. An involvement of melanins in stone surface penetration has been suggested, but not experimentally proved.
In this work, we tested the role of hyphal melanisation in penetration mechanisms on the model black fungus Knufia petricola A95 in lab conditions. The wild-type and three mutants with introduced targeted mutations of polyketide-synthases (melanin production) and/or phytoene dehydrogenase (carotenoid synthesis) were inoculated on artificial carbonate pellets (pressed Carrara marble powder) of different porosity. After 5, 10, 17 and 27 weeks, hyphal penetration depth and spread were quantified on periodic acid Schiff-stained cross-sections of the pellets, collecting measurements separately for TH and FH. Droplet assay of the mutants on different media were conducted to determine the role of nutrients in the development of different fungal morphologies.
In our in vitro study, the hyphal penetration depth, never exceeding 200 μm, was proven to be consistent with observed penetration patterns on stone heritage carbonate substrates. Pellet porosity affected penetration patterns of TH, which developed in voids of the more porous pellets, instead than actively opening new passageways. Oppositely, the thin diameter of FH allowed their penetration independently of substrate porosity.
Instead, the long-hypothesized crucial role of melanin in black MCF hyphal penetration should be rejected. TH were developed within the pellets also by melanin deficient strains, and melanized strains showed an endolithic component of non-melanized TH. FH were non-melanized for all the strains, but deeply penetrated all pellet types, with higher penetration depth probably related to their potential exploratory (nutrient-seeking) role, while TH may be more related to a resistance to surface stress factors. In the melanin deficient strains, the absence of melanin caused an increased penetration rate of FH, hypothetically related to an earlier necessity to search for organic nutrients.
... Historical building materials are porous materials like bricks, mortar, stones, and earth. Except for sudden destruction by natural disasters such as earthquakes, hurricanes, and floods, as well as damage by humans, animals, plants, and so on (Coutinho et al., 2015), most heritage buildings are subjected to material degradation through a multitude of physical and chemical processes (Wedekind et al., 2018), such as those initiated by exposure to microorganisms (Bartoli et al., 2014;Sterflinger et al., 2018), water, moisture, temperature, or salt (Araoka et al., 2017;Barone et al., 2015). Microorganisms make green, brown, and black spots on the surface of envelopes, which harm the aesthetic value of heritage buildings. ...
The historical, cultural, and social value of heritage buildings mandates special protection of these structures. Blue brick is one kind of the main construction materials of heritage buildings, which is porous material and easily subject to deterioration due to environmental factors such as humidity. Therefore, determining the dynamic moisture content rule of materials under fluctuant ambient humidity is necessary for preventative conservation. This study measured the equilibrium moisture content of eight types of Chinese blue bricks under isothermal conditions with varying humidity levels. The results show that when ambient humidity increased from 10% to 90%, the moisture sorption of historical Chinese blue bricks tripled, which is 3 times greater than that of modern Chinese blue bricks and 10 (at low humidity) to 20 times (at high humidity) greater than that of clay bricks in the international handbook. The results contribute to the improvement of the international building material database and research related to hygrothermal performance of heritage buildings in East Asia.
... All building materials may be subject to microbial colonization (Warscheid and Braams, 2000;Cutler and Viles, 2010;Jurado et al., 2014;Coutinho et al., 2015;Dedesko and Siegel, 2015;Guerra et al., 2019;Hu et al., 2019). Studies have been conducted to identify the microorganisms readily present on building materials in the BE. ...
Built environments, occupants, and microbiomes constitute a system of ecosystems with extensive interactions that impact one another. Understanding the interactions between these systems is essential to develop strategies for effective management of the built environment and its inhabitants to enhance public health and well-being. Numerous studies have been conducted to characterize the microbiomes of the built environment. This review summarizes current progress in understanding the interactions between attributes of built environments and occupant behaviors that shape the structure and dynamics of indoor microbial communities. In addition, this review also discusses the challenges and future research needs in the field of microbiomes of the built environment that necessitate research beyond the basic characterization of microbiomes in order to gain an understanding of the causal mechanisms between the built environment, occupants, and microbiomes, which will provide a knowledge base for the development of transformative intervention strategies toward healthy built environments. The pressing need to control the transmission of SARS-CoV-2 in indoor environments highlights the urgency and significance of understanding the complex interactions between the built environment, occupants, and microbiomes, which is the focus of this review.
... Next to physical and chemical damage, SABs cause considerable aesthetic damage on building materials. [81][82][83][84][85] Biocorrosion from SAB colonization has been estimated to account for 20% of all corrosion and may account for costs as much as tens of billions US dollars annually. [86][87][88] ll Studies recently uncovered information on the composition of SAB communities that develop on silicon PV panels. For example, research conducted in Sã o Paulo, Brazil, indicated that under humid, subtropical conditions, SABs were shown to develop on glass substrates of crystalline Si modules. ...
The low environmental impact of electricity generation using solar cells crucially depends on high energy-conversion efficiencies, long lifetimes, and a minimal energy and material demand during production. Emerging thin-film photovoltaics such as perovskites on plastic substrates could hold promises to fulfil all these requirements. Under real-world operating conditions, photovoltaic operation is challenged by biological stressors, which have not been incorporated for evaluation in any test. Such stressors cause biodeterioration, which impairs diverse, apparently inert materials such as rock, glass, and steel and therefore could significantly affect the function and stability of plastic-based solar cells. Given that different photovoltaic technologies commonly use similar materials, the biodeterioration mechanisms reviewed here may possibly affect the efficiency and lifetimes of several technologies if they occur sufficiently faster (during the expected lifetime of photovoltaics). Once the physical integrity of uppermost module layers is challenged by biofilm growth, microbially mediated dissolution and precipitation reactions of photovoltaic functional materials are very likely to occur. The biodeterioration of substrates and seals also represents emission points for the release of potentially harmful photovoltaic constituents to the environment.
... Thus, isolates that are in the same group can have the same growth and ecological strategies, share the same ecological niches, and use the same substrate. Similarly, Coutinho et al. [41] reported that strains belonging to the Alternaria, Cladosporium, Penicillium and Aspergillus genera were isolated on architectural ceramic material. These last two as primary colonizers of the substrate and r-strategists. ...
Fungal deterioration of building materials causes economic losses due to restoration processes and because it affects the health of the people exposed. Therefore, it is necessary to obtain highly deteriorating fungal strains to carry out studies focused on biodeterioration control. The aim of this research was to study the mycobiota involved in deterioration of facades through the isolation and characterization of fungal strains. In this sense, this paper characterizes the mycobiota that contributes to the deterioration of brick and concrete present in those places. Samples were taken from bricks and concrete with visible biodeterioration of the Cathedral of La Plata and the Experimental Station of the Centro de Investigación y Desarrollo en Tecnología de Pinturas. Relative density, apparition relative frequency, and ecological category of fungi isolates were determined. The deteriorating attributes were determined by carbonate dissolution test, pigment secretion assay, acid production test and brick weight variation. Cladosporium sp., Penicillium sp. and Aspergillus sp. were the taxa with the highest apparition relative frequency and abundance. Aspergillus niger MN371276, Lasiodiplodia theobromae MN371283, Cladosporium sphaerospermum MN371394, Penicillium commune MN371392 and Arthothelium spectabile MT071822 were the strains with the highest biodeteriorant activity. These strains can be used in studies on biodeterioration control of buildings materials.
... Colonization of man-made surfaces by algae and other biota negatively impacts their appearance and cause deterioration of the function [1][2][3]. To protect materials and surfaces, paints and coatings with various desirable properties are widely used in the building and paint industries. ...
Colonization of man-made surface materials by algae and other microorganisms, i.e. biofouling, causes various aesthetical and health problems as well as deterioration of appearance and surface functioning. The present study investigated eight complex surfaces combining various TiO2, alkoxy-siloxane and hydrophobization agents that were combined to prevent growth of phototrophic filamentous alga Klebsormidium sp. Regarding photoactivity, NOx abatement at the studied surfaces has been improved by adding anti-aggregation substances such as bentonite. Surface properties were characterized by confocal microscopy, scanning electron microscopy, SEM, with the energy dispersive X-ray spectroscopy, EDX, and the contact angle measurements. Biological experiments with Klebsormidium alga were performed in a constructed flow-through system. The results indicated that superhydrophobicity, i.e. very low surface energy, was critical for efficient antifouling during the early colonization by algae. This was specifically demonstrated in two novel composite samples made of titanium dioxide and commercial hydrophobization agent UltraEverDry. Low surface energy of these materials (around 1.3 mJ/m²), high water contact angles (>140°) as well as decent photoactivity (NOx conversions by 16.7 % and 1.4 % in UV and VIS, respectively), provide a promising basis for further longer-term anti-fouling experiments. The present study introduces novel composite materials preventing the algal fouling, and it brings new evidences on the interactive effects on hydrophobic and photoactive surfaces.
Fungi are ubiquitous and important biosphere inhabitants, and their abilities to decompose, degrade, and otherwise transform a massive range of organic and inorganic substances, including plant organic matter, rocks, and minerals, underpin their major significance as biodeteriogens in the built environment and of cultural heritage. Fungi are often the most obvious agents of cultural heritage biodeterioration with effects ranging from discoloration, staining, and biofouling to destruction of building components, historical artifacts, and artwork. Sporulation, morphological adaptations, and the explorative penetrative lifestyle of filamentous fungi enable efficient dispersal and colonization of solid substrates, while many species are able to withstand environmental stress factors such as desiccation, ultra-violet radiation, salinity, and potentially toxic organic and inorganic substances. Many can grow under nutrient-limited conditions, and many produce resistant cell forms that can survive through long periods of adverse conditions. The fungal lifestyle and chemoorganotrophic metabolism therefore enable adaptation and success in the frequently encountered extremophilic conditions that are associated with indoor and outdoor cultural heritage. Apart from free-living fungi, lichens are a fungal growth form and ubiquitous pioneer colonizers and biodeteriogens of outdoor materials, especially stone- and mineral-based building components. This article surveys the roles and significance of fungi in the biodeterioration of cultural heritage, with reference to the mechanisms involved and in relation to the range of substances encountered, as well as the methods by which fungal biodeterioration can be assessed and combated, and how certain fungal processes may be utilized in bioprotection.
Abstract – The hybrid isocyanate-free polyurethane/epoxy foams were obtained by reaction of
carbonized soybean oil and epoxies with diamines. The first stage involves the synthesis of carbonized
soybean oil, which was carried out by reaction of carbon dioxide with epoxidised oil in the presence of
tetrabutylammonium bromide (TBABr) as a catalyst. At the next stage, hydroxyurethane pre-polymers
were obtained by aminolysis of cyclic carbonate of soybean oil with diamines such as
aminoethylpiperazine (AEP) and isophorone diamine (IFDA). The adjusting of the molar ratio of IFDA,
AEP, compared to carbonized vegetable oil was carried out for receiving pre-polymers with structure
and physical properties, which are optimal for further reaction(s). At the last third stage, hybrid
NIPU/Epoxy foams were synthesized from hydroxyurethane prepolymer and epoxy resin, in presence
of polymethylhydrosiloxane (PMHS) as a reactive foaming agent. The final hybrid NIPU/Epoxy foams
were obtained by curing at 80 ◦C during 14 hours. The synthesized foams were investigated by FTIR and
DSC, TGA analysis
Intensive use of fossil-based energy sources causes significant environmental problems on a global scale. Researchers have been working for several decades to find alternative energy solutions to fossil fuels. Algae are a renewable energy source, with high potential for increasing scarce resources and reducing environmental problems caused by fossil fuel use. Algal Biotechnology for Fuel Applications gives the reader a comprehensive picture of the industrial use of algae for generating power. This book informs readers about the existence of alternative species to the currently used algae species for biofuel production, while also explaining the methods and current concepts in sustainable biofuel production. Key Features - Fifteen chapters covering topics on commercial algae species and algal biofuel production. - Covers anaerobic biotechnology and basic biofuel production from thermal liquefaction - Covers biodiesel production and algal biofuel characterization - Introduces the reader to applied microbial fuel cell technology and algae cultivation methods - Provides concepts about ecological engineering - Covers microalgae culture and biofuel production techniques - Explains the importance of catalysts - Explains the economic evaluation of algae fuel production technology This reference is essential reading for students and academics involved in environmental science, biotechnology, chemical engineering and sustainability education programs. It also serves as a reference for general readers who want to understand the ins and outs of algal biofuel technology.
Intensive use of fossil-based energy sources causes significant environmental problems on a global scale. Researchers have been working for several decades to find alternative energy solutions to fossil fuels. Algae are a renewable energy source, with high potential for increasing scarce resources and reducing environmental problems caused by fossil fuel use. Algal Biotechnology for Fuel Applications gives the reader a comprehensive picture of the industrial use of algae for generating power. This book informs readers about the existence of alternative species to the currently used algae species for biofuel production, while also explaining the methods and current concepts in sustainable biofuel production. Key Features - Fifteen chapters covering topics on commercial algae species and algal biofuel production. - Covers anaerobic biotechnology and basic biofuel production from thermal liquefaction - Covers biodiesel production and algal biofuel characterization - Introduces the reader to applied microbial fuel cell technology and algae cultivation methods - Provides concepts about ecological engineering - Covers microalgae culture and biofuel production techniques - Explains the importance of catalysts - Explains the economic evaluation of algae fuel production technology This reference is essential reading for students and academics involved in environmental science, biotechnology, chemical engineering and sustainability education programs. It also serves as a reference for general readers who want to understand the ins and outs of algal biofuel technology.
Intensive use of fossil-based energy sources causes significant environmental problems on a global scale. Researchers have been working for several decades to find alternative energy solutions to fossil fuels. Algae are a renewable energy source, with high potential for increasing scarce resources and reducing environmental problems caused by fossil fuel use. Algal Biotechnology for Fuel Applications gives the reader a comprehensive picture of the industrial use of algae for generating power. This book informs readers about the existence of alternative species to the currently used algae species for biofuel production, while also explaining the methods and current concepts in sustainable biofuel production. Key Features - Fifteen chapters covering topics on commercial algae species and algal biofuel production. - Covers anaerobic biotechnology and basic biofuel production from thermal liquefaction - Covers biodiesel production and algal biofuel characterization - Introduces the reader to applied microbial fuel cell technology and algae cultivation methods - Provides concepts about ecological engineering - Covers microalgae culture and biofuel production techniques - Explains the importance of catalysts - Explains the economic evaluation of algae fuel production technology This reference is essential reading for students and academics involved in environmental science, biotechnology, chemical engineering and sustainability education programs. It also serves as a reference for general readers who want to understand the ins and outs of algal biofuel technology.
The purpose of this study was to provide an empirical failure model predicting the microalgae growth on fired bricks surfaces. It was developed through a numerical fitting of experimental data present in literature. It considered the substrate properties related to biofouling (i.e. porosity and roughness) of different bricks under several environmental conditions (i.e. relative humidity and temperature). Results shows that the model is able to simulate the microalgae biofouling by explicitly taking into account such influencing factor. Finally, this empirical failure model is validated on a different dataset from literature and applied to time varying temperature.
The Museu Imperial has an important historical collection from the Portuguese Royal Family in Brazil. The throne represents the imperial power and is considered one of the most important objects in the museum; however, the piece has been facing for decades a gradual deterioration, mainly in its fabrics. With the growing motivation to preserve this property, conservation and restoration processes were conducted in all parts of the throne. As a part of this treatment, a microbiological survey was conducted in selected parts of the object and the surrounding environment where it was placed. This biodeterioration study, control and detection of microbial species indicated a very pertinent answer in relation to the place it was exposed, and the restoration process was performed in order to solve the most pronounced damages aiming to restore the original characteristics of the artefact. The study indicated a high diversity of fungi and bacteria. It was observed a marked decrease, before and after restoration, being observed the recurrence of the genera Absidia, Cladosporium and Epicoccum. This reduction was not so pronounced for bacteria, being also observed the recurrence of some bacterial groups after restoration (Microbacterium, Staphylococcus and Kocuria). In the atmosphere new fungal species were found after restoration, indicating a natural recontamination of the exhibition area.
Biodeterioration challenges range from poor indoor air quality and exterior marble defacing to more dangerous building degradation. People often change the look of degraded walls by painting over them, removing carpets as well as replacing damaged wood and papers to improve their aesthetic value. Due to a lack of public awareness and health care infrastructure, the degradation rate is increasing in many countries. There is a need for a review of the international literature supporting practical recommendations. In this critical review paper, the role of microbes in deteriorating buildings, their health impacts in terms of mycotoxins and diverse strategies to handle them are discussed. Moreover, the forthcoming challenges associated with biodegradation and their health impacts have been addressed. Key recommendations have been made: (a) increase of awareness due to community involvement in enhancing moisture control, (b) improvement of cleaning processes and the use of air conditioning systems, (c) regular inspection and maintenance regimes for buildings and (d) cleaning of heating and air conditioning units and associated replacements of filters. The review provides a broad overview of the subject area and should be of interests to generalists working in a wide range of disciplines relevant to indoor air quality.
After they have been abandoned, ceramic materials may undergo substantial transformations, all of which may change their macroscopic aspect, mineralogy, chemical composition and microstructure. The intensity and pervasiveness of these transformations on both macro- and micro-scales depend to a great extent not only on their compositional and microstructural features but also on the chemical-physical characteristics of the post-depositional environment in which they were hosted. This contribution describes the main post-depositional transformations observed in ancient ceramics in relation to secondary phases precipitation, mineral dissolution, pristine mineral and amorphous phases transformations into new mineral phases, and chemical leaching and enrichment. The mechanisms responsible for these transformations are described, together with the characteristics which allow us to identify them according to the most common analytical approaches, in order not to introduce misleading interpretations concerning the study of the provenance and production technology of ancient ceramic materials.
Because microbes cannot be eliminated from radioactive waste disposal facilities, the consequences of bio-colonization must be understood. At a pre-Viking era vitrified hillfort, Broborg, Sweden, anthropogenic glass has been subjected to bio-colonization for over 1,500 years. Broborg is used as a habitat analogue for disposed radioactive waste glass to inform how microbial processes might influence long-term glass durability. Electron microscopy and DNA sequencing of surficial material from the Broborg vitrified wall, adjacent soil, and general topsoil show that the ancient glass supports a niche microbial community of bacteria, fungi, and protists potentially involved in glass alteration. Communities associated with the vitrified wall are distinct and less diverse than soil communities. The vitrified niche of the wall and adjacent soil are dominated by lichens, lichen-associated microbes, and other epilithic, endolithic, and epigeic organisms. These organisms exhibit potential bio-corrosive properties, including silicate dissolution, extraction of essential elements, and secretion of geochemically reactive organic acids, that could be detrimental to glass durability. However, long-term biofilms can also possess a homeostatic function that could limit glass alteration. This study documents potential impacts that microbial colonization and niche partitioning can have on glass alteration, and subsequent release of radionuclides from a disposal facility for vitrified radioactive waste.
Antiquities and monuments are represents of the culture, civilization and historical background of a country and can be very effective in economic growth and development of countries. It is very important to protect these monuments and if not to be noticed, will be causes serious and irreversible destruction. In recent years, chemical and physical factors also biological factors are introduced as very important and effective factors in biodeterioration. The issue of biodeterioration is one of the problems that cultural heritage always faced to it. Biodeterioration is an irreversible damage caused by microorganisms against archaeological sites. This worldwide problem, resulting to the physical and chemical damage in historical/ archaeological substrates and artworks. The role of various microorganisms has been proven in the erosion of a variety of artistic and historical substrate, including paintings, stone works, ceramics, paper documents and books, wood, textiles and films. The first step in controlling microbial deterioration of monuments is to identify deteriorating microorganisms and to know their mechanisms in the deterioration of archaeological substrates and artworks.
This subject provides a valuable information for restorators and researchers in choosing the most appropriate methods for the prevention, control and treatment of damage on substrates.
This article is an overview to introduce the most important microorganisms and to know their mechanisms of microbial deterioration of various historical and artistic substrates.
Novel species of fungi described in the present study include the following from Australia: Vermiculariopsiella eucalypti, Mulderomyces natalis (incl. Mulderomyces gen. nov.), Fusicladium paraamoenum, Neotrimmatostroma paraexcentricum, and Pseudophloeospora eucalyptorum on leaves of Eucalyptus spp., Anungitea grevilleae (on leaves of Grevillea sp.), Pyrenochaeta acaciae (on leaves of Acacia sp.), and Brunneocarpos banksiae (incl. Brunneocarpos gen. nov.) on cones of Banksia attenuata. Novel foliicolous taxa from South Africa include Neosulcatispora strelitziae (on Strelitzia nicolai), Colletotrichum ledebouriae (on Ledebouria floridunda), Cylindrosympodioides brabejum (incl. Cylindrosympodioides gen. nov.) on Brabejum stellatifolium, Sclerostagonospora ericae (on Erica sp.), Setophoma cyperi (on Cyperus sphaerocephala), and Phaeosphaeria breonadiae (on Breonadia microcephala). Novelties described from Robben Island (South Africa) include Wojnowiciella cissampeli and Diaporthe cissampeli (both on Cissampelos capensis), Phaeotheca salicorniae (on Salicornia meyeriana), Paracylindrocarpon aloicola (incl. Paracylindrocarpon gen. nov.) on Aloe sp., and Libertasomyces myopori (incl. Libertasomyces gen. nov.) on Myoporum serratum. Several novelties are recorded from La Réunion (France), namely Phaeosphaeriopsis agapanthi (on Agapanthus sp.), Roussoella solani (on Solanum mauritianum), Vermiculariopsiella acaciae (on Acacia heterophylla), Dothiorella acacicola (on Acacia mearnsii), Chalara clidemiae (on Clidemia hirta), Cytospora tibouchinae (on Tibouchina semidecandra), Diaporthe ocoteae (on Ocotea obtusata), Castanediella eucalypticola, Phaeophleospora eucalypticola and Fusicladium eucalypticola (on Eucalyptus robusta), Lareunionomyces syzygii (incl. Lareunionomyces gen. nov.) and Parawiesneriomyces syzygii (incl. Parawiesneriomyces gen. nov.) on leaves of Syzygium jambos. Novel taxa from the USA include Meristemomyces arctostaphylos (on Arctostaphylos patula), Ochroconis dracaenae (on Dracaena reflexa), Rasamsonia columbiensis (air of a hotel conference room), Paecilomyces tabacinus (on Nicotiana tabacum), Toxicocladosporium hominis (from human broncoalveolar lavage fluid), Nothophoma macrospora (from respiratory secretion of a patient with pneumonia), and Penidiellopsis radicularis (incl. Penidiellopsis gen. nov.) from a human nail. Novel taxa described from Malaysia include Prosopidicola albizziae (on Albizzia falcataria), Proxipyricularia asari (on Asarum sp.), Diaporthe passifloricola (on Passiflora foetida), Paramycoleptodiscus albizziae (incl. Paramycoleptodiscus gen. nov.) on Albizzia falcataria, and Malaysiasca phaii (incl. Malaysiasca gen. nov.) on Phaius reflexipetalus. Two species are newly described from human patients in the Czech Republic, namely Microascus longicollis (from toenails of patient with suspected onychomycosis), and Chrysosporium echinulatum (from sole skin of patient). Furthermore, Alternaria quercicola is described on leaves of Quercus brantii (Iran), Stemphylium beticola on leaves of Beta vulgaris (The Netherlands), Scleroderma capeverdeanum on soil (Cape Verde Islands), Scleroderma dunensis on soil, and Blastobotrys meliponae from bee honey (Brazil), Ganoderma mbrekobenum on angiosperms (Ghana), Geoglossum raitviirii and Entoloma kruticianum on soil (Russia), Priceomyces vitoshaensis on Pterostichus melas (Carabidae) (Bulgaria) is the only one for which the family is listed, Ganoderma ecuadoriense on decaying wood (Ecuador), Thyrostroma cornicola on Cornus officinalis (Korea), Cercophora vinosa on decorticated branch of Salix sp. (France), Coprinus pinetorum, Coprinus littoralis and Xerocomellus poederi on soil (Spain). Two new genera from Colombia include Helminthosporiella and Uwemyces on leaves of Elaeis oleifera. Two species are described from India, namely Russula intervenosa (ectomycorrhizal with Shorea robusta), and Crinipellis odorata (on bark of Mytragyna parviflora). Novelties from Thailand include Cyphellophora gamsii (on leaf litter), Pisolithus aureosericeus and Corynascus citrinus (on soil). Two species are newly described from Citrus in Italy, namely Dendryphiella paravinosa on Citrus sinensis, and Ramularia citricola on Citrus floridana. Morphological and culture characteristics along with ITS nrDNA barcodes are provided for all taxa.
Biological colonization of roofing tiles affects not only the aesthetic aspect of the roof but also its functionality. Complex microbial communities naturally develop on roofing tiles constituting the first stage in the colonization of these building materials. Herein, we analyzed the composition of natural microbial communities developed on roofing tiles aiming to be able to reproduce the colonization process as a method to evaluate the bioreceptivity of roofing tile materials. Bacteria, fungi, microalgae, and cyanobacteria obtained from naturally colonized roofing tiles were isolated, cultured and characterized by DNA-based molecular analysis using the small subunit of the ribosomal RNA gene (16S and 18S for prokaryotes and eukaryotes, respectively). Several isolates of Streptomyces sp. (Actinobacteria), Fusarium sp. (Ascomycota), and mixed cultures of phototrophic microorganisms were assayed for their capability to colonize roofing tiles. Our results demonstrate that roofing tiles are highly bioreceptive to microbial colonization and that the process can be reproduced under laboratory conditions.
This paper offers a review on durability of fired clay brick masonry wall due to salt attack. Durability of brick normally affected when an external masonry walls are exposed to aggressive environment. Masonry structures, when subjected to salt attack or exposed to aggressive environment during their service life may suffer degradation due to the formation of crystallization pressure as a result of the evaporation of soluble salt in clay masonry structures. The crystallization pressures produce normally higher than tensile stress of clay brick and sufficient to damage the masonry structures. The mechanism of salt attack must be prevented and addressed thoroughly in order to maintain the integrity and service life of masonry wall. Therefore, the summary of durability, factors, mechanism and main sources of salt attack on fired clay brick masonry walls are discussed.
Decorative panels of ceramic glazed tiles comprise a valuable cultural heritage in Mediterranean countries. Their preservation requires the development of a systematic scientific approach. Exposure to an open-air environment allows for a large span of deterioration effects. Successfully overcoming these effects demands a careful identification of involved degradation processes. Among these, the development of micro-organisms and concomitant glaze surface staining is a very common effect observed in panels manufactured centuries ago. This paper describes a study on the nature of green stains appearing at the surface of blue-and-white tile glazes from a large decorative panel with more than one thousand tiles, called Vista de Lisboa that depicts the city before the destruction caused by the 1755 earthquake. The characterization of green-stained blue-and-white tile glazes was performed using non-destructive X-ray techniques (diffraction and fluorescence spectrometry) by directly irradiating the surface of small tile fragments, complemented by a destructive scanning electron microscopy (SEM) observation of one fragment. Despite the green staining, analytical X-ray data showed that no deterioration had occurred irrespective of the blue or white color, while complementary SEM-EDX data provided chemical evidence of microorganism colonization at the stained glaze surface.
A group of late 15theearly 16th century Hispano-Moresque glazed tiles from the Monastery of Santa Clara-a-Velha, in Coimbra, were, for the first time, characterised chemically and morphologically. Since the prevailing idea among art historians in Portugal is to judge the Hispano-Moresque tile heritage as Spanish production, the findings concerning technological processes were compared with the Islamic technology in the Iberian Peninsula and latter Hispano-Moresque in Spain. This study is the first analytical indicator of a production technology with some differences from the Hispano-Moresque workshops (such as Seville, Toledo, etc.) and points out to a possible local production. Five different coloured glazes were identified: white, blue, green, amber and black, all displaying high-lead content, as expected for this type of ceramics. Tin oxide was identified in high contents (7e14 wt.%) in white and blue glazes, its crystals homogenously distributed in also very homogeneous glazes, showing similarities with an Islamic glazing technology. On the other hand, Ca-rich thick glazeeceramic interfaces were observed, with many mineral inclusions (wollastonite (CaSiO 3) and also K-feldspars (general formula KAlSi 3 O 8), showing a higher resemblance with a later Hispano-Moresque technology. Other compounds were also identified from reactions involving the colour compound: malayaite (CaSnOSiO 4), bustamite (CaMnSi 2 O 6), braunite ((Mn 2þ , Mn 3þ) 6 O 8 SiO 4), andradite (Ca 3 Fe 2 Si 3 O 12), magnesioferrite (MgFe 2 O 4) and a nickel ferrite (NiFe 2 O 4). The chemical composition of this glazeeceramic interface suggests firing temperatures between 950 C and 1000 C and its thickness implies a single-fire process. The chemical characterisation does not suggest different recipes or different firing processes for cuerda seca and arista tiles.
The study illustrates both the biodeterioration and biomineralization actions of
two fungus species (Aspergillus niger and Cladosporium sp.) and two organic
acids (oxalic and acetic) and the action of the frost (frost dilatation studies in
laboratory conditions) as the main factors of the process of ageing of clay
roofing tiles. The nano-crystalline products, formed in this way, contribute to the
abundant reactive surface area of the existing and new filled pores (due to the
fungus hyphen penetration into the ceramic support) deepening the ageing
processes of the clay roofing tiles.
A relationship between the textural and microstructural characteristics of the
studied systems and the formation of the specific crystal forms, developed after
the actions of fungus, and oxalic/acetic acids was set up.
Keywords: biodeterioration, lichen, fungi, oxalic acid, acetic acid, clay roofing
tiles.
1 Introduction
Cultural heritage objects were made with almost all type of materials produced
by nature and used by men to realize several types of artefacts of very simple
mono-components and of complex structure, integrating inorganic and organic
matter. These objects, even if they were made of more \“resistant” stones, mortars
and ceramic materials, are influenced by the environmental parameters, which
can modify their structure and composition. Furthermore, inserted into the
\“biosphere” they can be decayed by biological mechanisms. Clay roofing tiles,
as a part of this world, support large and diverse communities of microorganisms
that colonize both the tile surface and the porous interior. Their weathering, as a
result of organic acid exudation by lichens, fungi and bacteria, is recognized as a
Frost resistance of roofing tiles is of both practical and scientific interest, especially since the frost action mechanisms are still not well understood. Textural characteristics and low temperature dilatometrical behavior (from -40 to +40 o C) of clay roofing tiles are correlated with the type of frost damage identified by the standard procedure, EN 539-2, method C, giving the insight in dominating frost action mechanism (mechanism of closed container, hydraulic pressure, and micro ice lens mechanism). The samples of clay roofing tiles from the same batch were fired in laboratory conditions at different temperatures (920, 970, 995, 1015, 1055 and 1085 o C) and in the industrial plant (cca 1100 o C). Based on the mentioned correlations, the change of dominating frost action mechanism is explained by porous structure differentiation with the temperature, from closed container at lower to micro ice lens formation at higher temperatures, the hydraulic pressure mechanism contributing considerably on all the temperatures. The obtained correlations are of specific importance in taking fast and right corrective measures in defined production line in order to improve the frost resistance characteristics of the final product.
The objective of this study was to examine the effect of the hydroxyl radicals (free and bound) produced by a TiO 2 mesoporous coating immobilized on the surface of clay roofing tiles. The efficiency of the coating was determined by microbiological and photochemical tests. In the microbiological test (pour plate method), use was made of the test bacteria Pseudomonas aeruginosa, while the photochemical test involved the degradation of para-chlorobenzoic acid, monitored by HPLC method. Both experiments were carried out without and with a scavenger (methanol and tert-butanol). The results of the measurement of the photocatalytic efficiency, and the observed changes in the measured contact angle (sessile drop method), imply the existence of a photo-induced hydrophilicity of the TiO 2 coated porous substrates. The newly designed coating represents a medium which efficiently hinders bacterial adhesion. The experiments demonstrated the existence of self-cleaning and slight self-disinfecting properties of the mesoporous coating.
Oxalate is a key metabolite that plays a significant role in many metal and mineral transformations mediated by fungi. Metal and mineral transformations are central to geomycological processes including nutrient and element cycling, rock, mineral and metal transformations, bioweathering and mycogenic biomineral formation. Some fungal transformations have potential applications in environmental biotechnology, e.g. metal and radionuclide leaching, biorecovery, detoxification and bioremediation, and in the production or deposition of biominerals or metallic elements with catalytic or other properties. Metal and mineral transformations may also result in adverse effects when these processes result in biodeterioration of natural and synthetic materials, rock and mineral-based building materials (e.g. concrete), biocorrosion of metals, alloys and related substances, and adverse effects on radionuclide speciation, mobility and containment. Oxalate is ubiquitous in all these contexts. This paper seeks to draw together salient information from environmental and applied research to emphasize the importance of oxalate in geomycology, biodeterioration, environmental biotechnology and bioremediation.
Understanding the origin and evolution of the eukaryotic cell and the full diversity of eukaryotes is relevant to many biological disciplines. However, our current understanding of eukaryotic genomes is extremely biased, leading to a skewed view of eukaryotic biology. We argue that a phylogeny-driven initiative to cover the full eukaryotic diversity is needed to overcome this bias. We encourage the community: (i) to sequence a representative of the neglected groups available at public culture collections, (ii) to increase our culturing efforts, and (iii) to embrace single cell genomics to access organisms refractory to propagation in culture. We hope that the community will welcome this proposal, explore the approaches suggested, and join efforts to sequence the full diversity of eukaryotes.
During the 19th century, the most prominent buildings of the city of Belém were faced entirely with tiles manufactured in Portugal and Germany, which now exhibit distinct degrees of degradation. The Pinho mansion is one of the most important of these buildings and was selected for the investigation of the action of the tropical Amazonian climate on the degradation of the tiles. To achieve this objective, the tiles were mapped for organic and inorganic degradation, and samples were collected for analysis. The minerals were determined by XRD, the chemical composition by classical wet methods and SEM/EDS, and the microorganisms under the microscope. The results show that the German and Portuguese tiles are quite different in their composition. While both ceramic bodies are composed of SiO2 and Al2O3, CaO was found only in the Portuguese tile. The low Na2O and K2O contents indicate the addition of materials to reduce the fusion temperature. SiO2 and PbO are the main constituents of the glaze, with CoO and FeO being added as pigment. The ceramic body of the German tiles is constituted of quartz, mullite, and cristobalite, in contrast with the Portuguese tiles, which are made of quartz, gehlenite, diopside, calcite, and feldspars. The glazes are XRD-amorphous. The chemical and mineralogical differences between the German and Portuguese tiles indicate that they were produced from different raw materials under distinct thermal processes. The most prominent weathering-related modifications are the thin layers (German tiles), oxidation stains, dark stains, the detachment of the tile (Portuguese tiles), loss of the glaze and powdering of the ceramic body (Portuguese tiles) through the establishment of Cyanophyta and Bacillariophyta.. The distinct degradation patterns of the tiles exposed to the tropical Amazon climate are a consequence of their distinct mineralogy and chemistry.
Due to the fact that there are various types of wall tiles in the Egyptian market, of different qualities and prices, the aim of this research paper is to evaluate the properties and characteristics of tiles obtained from the local Egyptian market and attempt to identify the reasons for such differences. In other words, investigate the reasons why some tiles are more superior in quality than others. Test specimens were obtained from the local Egyptian market for fourteen factories. The mechanical properties (namely flexural strength) and physical properties (namely water absorption and apparent porosity) were measured, as they reflect the strength, the endurance during handling, as well as, the conditions to which the tiles are expected to be exposed to during use. The impact resistance and hardness were tested as well. Also, the phases (both major and minor) developed during the firing (maturing) step of manufacturing were identified. A correlation was made between the measured properties and the formed phases. The results showed that samples which yielded high physical and mechanical properties are those that constituted mainly the major phases, specifically, mullite and quartz, while those that contained impurities in the raw materials inevitably resulted in the development of minor phases, in addition to the major phases, had a negative effect on the measured properties. Consequently, it is feasible to obtain tiles that satisfy the requirements of ISO 13006 specification provided that the used raw materials are free (as much as possible) from impurities such as hematite, magnesium, and calcium.
For two strains, the green alga Pleurococcus CVB4 and the cyanobacterium Lyngbya CCB2, isolated from the pioneering algal biocoenosis present on a marble statue, we determined the optimum range of growth in selective cultural media in relation to pH, light intensity, and temperature, together with the ability of these organisms to colonize stone surfaces that differed either in the structure-texture or in the physico-chemical composition of the various lithotypes. The results showed a higher capacity of the green alga to withstand environmental factor changes. For both organisms the preferential colonization of the stone surface was correlated primarily, together with the environmental factors (pH, temperature, irradiance), to the physical characteristics (roughness and porosity) and secondarily to the chemical composition of the assayed lithotypes.
Heritage building is a valued property because it symbolizes the national culture, history and identity. Conservation and preservation of the heritage features should be continued. Malaysia has much type of traditional houses which placed in every state. The uniqueness of the traditional Malay house is full with its own aesthetic value that is not bad the passage of time. Traditional Malay house is greatly influenced by environmental factors, including encouraging the flow and transition air, natural lighting, reduce direct sunlight and rain as well as energy-efficient home designs. Singgora roof is an architecture that preserves the traditional heritage in its design. Singgora is a roof made of clay on foot, comes from the Malay name called Singgora which means “Lion City” and was physically Singgora taken from the appearance of fish scales. It is well known in East Coast states and Thailand. The use of roof Singgora now fading because the problems that arise in terms of material strength, quality, fungal problems and the life expectancy. Conservation on the roof Singgora take a long time because it involves the process of open, treat, and then re-install the replacement. Therefore, the conservation of heritage building's roof requires high cost and time. This research was done through a process, method, main ingredient, strength and lifetime of the roof Singgora and maintaining the heritage character. The use of supplement material added to strengthen and the quality to the roof. Research findings will be documented to preserve the heritage and traditional values heritage building in Malaysia.
Microorganisms (bacteria, archaea and fungi), in addition to lichens and insect pests, cause problems in the conservation of cultural heritage because of their biodeteriorative potential. This holds true for all types of historic artefacts, and even for art made of modern materials, in public buildings, museums and private art collections. The variety of biodeterioration phenomena observed on materials of cultural heritage is determined by several factors, such as the chemical composition and nature of the material itself, the climate and exposure of the object, in addition to the manner and frequency of surface cleaning and housekeeping in museums. This study offers a review of a variety of well-known biodeterioration phenomena observed on different materials, such as stone and building materials, objects exhibited in museums and libraries, as well as human remains and burial-related materials. The decontamination of infected artefacts, exhibition rooms and depots incurs high expenditure for museums. Nevertheless, the question has to be raised: whether the process of biodeterioration of cultural heritage can or should be stopped under all circumstances, or whether we have to accept it as a natural and an implicit consecution of its creation. This study also highlights critically the pros and cons of biocide treatments and gives some prominent examples of successful and unsuccessful conservation treatments. Furthermore, an outlook on the future research needs and developments in this highly interesting field is given.
Culture-dependent methods for bacterial community analysis are currently considered obsolete; therefore, molecular techniques are usually used instead. The results of the current study on hydrocarbonoclastic bacteria in various oily habitats in Kuwait showed however, that the bacterial identities varied dramatically according to the analytical approach used. For six desert and six seawater samples used in this study, the culture-independent and culture-dependent techniques each led to a unique bacterial composition. Problems related to the culture-dependent technique are well known. The results of the current study highlighted bias problems other than those already recorded in the literature for the molecular approaches. Thus, for example, in contrast to the culture-dependent technique, the primers used in the molecular approach preferentially amplified the 16S rDNAs of hydrocarbonoclastic bacteria in total genomic DNAs of all the studied environmental samples, and in addition, failed to reveal in any environmental sample members of the Actinobacteria. The primers used in the molecular approach also amplified certain "pure" 16S rDNAs, but failed to do so when these DNAs were in mixture. In view of these results, it is recommended that the two analytical approaches should be used simultaneously because their combined results would reflect the bacterial community composition more precisely than either of them can do alone.
The effect of the actions of some lichens on the quality of ceramic roofing tiles was investigated in view of textural and microstructural changes considering their bio-corrosion resistance. Two types (extruded and pressed) of the real ceramic roofing tiles aged 6 to 10 years, as well as the ceramic model systems formed with the additives of the specific chemical composition Cu-slag powder (10 wt%) and CuO powder (1 wt%), treated with various concentrations of oxalic acid (0.01 wt%, 0.1 wt%, and 4 wt%) were investigated. The thalli of lichen (Verrucaria nigrescens) growth on ceramic roofing tile were examined by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Investigation by SEM and EDS gave information regarding the ultrastructure characteristics of the thallus and the lichen-ceramic tile contact zone, allowing the observation of the hyphal penetration and filling up of the fissures and cracks by the lichens' hyphae. The CuO as the raw mixture additive changed the quality of the surface of the ceramic model systems as it has increased resistance to oxalic acid actions. The textural changes in the ceramic model systems and the formation of the identified destructive crystal phase, whewellite, were slowed down. The fundamental interactions between lichens and ceramic materials of the model systems have been identified as physico-chemical processes based on oxalic acid actions, which could cause ceramic matrix deterioration and consequently aging of ceramic roofing tile systems.
A detailed account of lichens growing on different artifacts in the Indian subcontinent is provided. Some interesting distributional and ecological patterns of lichens growing on historical monuments and buildings are also presented.
The importance of microbial impacts in the alteration and deterioration of cultural artefacts made of mineral, metallic or organic materials has been widely acknowledged in the course of many recent investigations. While in the past biodeterioration problems on cultural artefacts were often handled without a detailed analysis and, as a consequence, simply controlled by biocidal treatments, a much deeper interdisciplinary understanding of the environmental factors and material properties regulating the biogenic damage factor would allow more specific and adequate interventions. The upcoming possibilities and potential realisation of integrated concepts in the protection of cultural artefacts against biodeterioration will be basically explained with the analytical and evaluating approach and will be exemplified by the presentation of case studies dealing with the conservation of historical objects made of natural stones, wall-paintings, historical glass, archives (e.g. paper, leather, parchment) and organic coatings.
The effect of lichens on the quality of ceramic roofing tiles was investigated with respect to textural changes and low temperature dilatation values. For this purpose, two types of ceramic roofing tiles (extruded and pressed) aged 6 to 10 years were examined, as well as ceramic model systems formed with Cu-slag and Cu-oxide powder additions. The identified lichen family was Verrucariales. The fundamental interactions between lichens and the ceramic materials have been identified as the physicochemical processes based on oxalic acid action which cause the aging and finally the destruction of materials. Cu-oxide as the raw mixture additive changed the quality of the surface tile, having a positive effect on the response of the ceramic tiles to the oxalic acid action. The textural modifications and the formation of the identified destructive crystal phase, whewellite, were slowed.
Terrestrial cyanobacteria and microalgae in Roman hypogea are possibly the first colonizers of the exposed surfaces and their extensive development is supported by the mineral composition of the substrata and the porous nature of calcareous surfaces. The strategies for the adhesion to the stone are based on the production and secretion of mucilaginous compounds at the cell surface. Exopolymeric substances (EPS) secreted by the microorganisms) act in sticking the cells to the substratum, and their adhesive properties contribute to the formation and cohesion of biofilms. A polysaccharide matrix containing cell debris and significant amounts of inorganic material adsorbed from the substrate makes up most of the cyanobacterial films to which airborne particles, bacteria, and spores adheres, which increases masking effects, transformation, and corrosion of the surfaces. This chapter describes studies performed on polysaccharide fractions of selected cyanobacterial species from Roman hypogea to gain preliminary information on their physicochemical characteristics by using circular dichroism. Cyanobacterial polysaccharides were studied in Leptolyngbya sp. that was isolated from Catacombs of St. Sebastian in Rome. After harvesting of cultures and culture media by centrifugation, polysaccharide extraction was performed to obtain three fractions: the polysaccharides in solution, released polysaccharides (RPS) and the envelope polysaccharides, capsular polysaccharides (CPSc= cold extract and CPSh= hot extract). The contribution of released (RPS) and capsular (CPS) polysaccharides to total biomass was calculated and circular dichroism spectra of the three extractable polysaccharide fractions were analyzed. All fractions showed the presence of uronic acids and CPS of sulfated residues. No evidence of temperature dependence was found, while low pH values caused an irreversible change in the polysaccharide molecular conformation.
Poikilohydric plants are those in which water status is completely dependent on their environment (Walter 1931) so that, in terrestrial habitats, the water vapor partial pressure of the plant body comes into equilibrium with the humidity of the atmosphere. These plants must be able to tolerate some desiccation although the minimum water potentials reached will depend on the environment and some poikilohydric plants may not be desiccation-tolerant (Green et al. 1991). In contrast, homoiohydric, terrestrial, vascular plants maintain their water status within fairly tight limits. Poikilohydry is exhibited by some ferns, club mosses, and even several phanerogams, but the major groups are algae, cyanobacteria (e.g., cyanobacterial mats), fungi and, of course, lichens, and bryophytes. Taxonomically, lichens and bryophytes are widely separated since, under presently accepted systems of classification (Raven et al. 1986), they fall into two separate Kingdoms; lichens in the Mycota and bryophytes in the Plantae. The situation is further complicated by the phycobionts of lichens which may be in the Monera (cyanobacteria) or Protista (chlorophyta) or in both, when multiple photobionts are present.
Line defects in a crystalline material are known as dislocations (unless they’re disclinations, which we ignore because they’re much more difficult and not nearly as important in ceramics). In contrast to point defects, dislocations never exist in thermodynamic equilibrium because they have formation energies of ~1 eV (or more) per atom along the line and there is no significant balancing entropy contribution as there is for point defects. They are almost always present in crystals because of how the crystal grew or because it was deformed. Dislocations thus usually form due to nonequilibrium conditions, such as thermal and mechanical processing, or for thin films and single crystals, during growth. There are two special types of dislocation.
Cleaning methods are assessed for Dutch tin-glazed earthenware where the glaze has been blackened by burial in anaerobic environments, primarily cess-pits and canals. The blackening has been shown, by X-ray diffraction (XRD), electron diffraction and scanning electron microscopy (SEM), to result from the formation of crystalline lead sulphide particles within the glaze. The efficacy of chemical methods designed to transform or remove the lead sulphide blackening was investigated in laboratory experiments with AnalaR-grade lead sulphide and with excavated Delftware shards. By means of SEM, transmission electron microscopy (TEM), XRD and laboratory observations, it was concluded that: (i) mineral acids (notably nitric) can give visually acceptable cleaning but destroy the integrity of the ceramic body by removing calcite or dolomite; (ii) citric acid and tartaric acid, although less damaging to the ceramic body, are inefficient cleaning reagents; (iii) hydrogen peroxide partially restores the original glaze colours, by transformation of lead sulphide to lead sulphate, with no apparent detriment to the ceramic body; (iv) sodium hydroxide (5M) achieves effective cleaning with minimal apparent damage to the ceramic body. During these investigations the presence of carbon filaments in the earthenware matrix of one shard was observed by TEM. In preliminary experiments designed to assess alternatives to chemical cleaning, refiring of blackened shards at c. 950°C restored the original glaze appearance effectively. The potential of neutron autoradiography as a means of visualizing glaze designs is also discussed.
The blackish brown crust on the fine carvings of seven terracotta monuments of Bishnupur were studied with regards to the presence of algal species. Forty five taxa of micro algae belonging to 36 species of cyanobacteria, 5 species of chlorophyta and 4 species of bacillariophyta were found in crusts of these monuments. Among the algal groups, cyanobacteria were the dominant population growing in all the monuments with maximum diversity of 30 species in Rasmancha. Lyngbya corticicola, Scytonema schmidtii and Nostoc microscopicum were the major taxa in all crust samples. The absorption ratio of chlorophyll: carotenoid: MAAs (mycosporine-like amino acid substances) and scytonemin showed scytonemin and MAAs were more abundant than the chlorophyll pigment in all the crust. The MAAs and scytonemin of the crusts were identified as Mycosporine glycine having absorption maxima at 310 nm with retention time (RT) 4.1 min and scytonine having absorption maxima 386 nm with RT 3.2 min respectively. Among the major crust cyanobacteria cellular carbohydrate of N. microscopicum was maximum and lowest in S. schmidtii. However, the extra polymeric substance released to the medium was more in L. corticicola and so intense that the medium become coloured. The slimes of the major crust cyanobacteria plug the fine carvings of the terracotta structures which led to disfiguration of fine architecture, act as a biofilm that facilitated growth of fungi, lichens and subsequently to mosses and small plants leading to create creaks in the monuments and deteriorate these archeologically important monuments. (c) 2012 Elsevier Ltd. All rights reserved.
Conserving the cultural heritage is a general concern and the use of non-destructive techniques to characterize ancient materials is important. Serious deterioration effects in environmentally exposed ancient glazed ceramic tiles arise from the development of micro-organisms (algae/fungi) within the pore system. Subsequent biodegradation processes are particularly harmful once the decorated glaze is damaged by exfoliation/detachment.Three case studies will be addressed: Portuguese polychrome decorated tiles from the interior of two churches (16th-17th century) and from the outdoor of a Palace (18th century). Small tile fragments were directly irradiated in a wavelength-dispersive X-ray fluorescence spectrometer for glaze chemical characterization and subsequently irradiated in a powder diffractometer to assess the phase constitution of both glaze and ceramic body.Cleaning and conserving these ancient cultural artifacts involve a decontamination process applying innovative non-destructive techniques. The present work is intended as a contribution to diagnose the actual degradation state of ancient tiles in view of future decontamination actions using gamma radiation.
The aim of this work was to analyze the bacterial communities in four samples of historical materials (plaster, brick, and wood) derived from buildings located in the former Auschwitz II–Birkenau concentration and extermination camp in Brzezinka, Poland. For this purpose a molecular strategy based on the construction of 16S rRNA clone libraries was used. In total, 138 partial 16S rRNA gene sequences (∼600 bp) were obtained and compared. The clones belonged to phyla Proteobacteria (classes: Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria), Actinobacteria, Firmicutes, and Bacteroidetes. The plaster samples predominantly contained clones closely related to Actinobacteria and Alphaproteobacteria, brick samples contained Gammaproteobacteria, while wood samples had Actinobacteria clones. Interestingly, the historic plaster and brick samples contained the following bacteria with known and described biodeterioration potential: chemoorganotrophic Streptomyces sp. and Pseudonocardia sp., halotolerant or halophilic Rubrobacter sp., Salinisphaera sp. and Halomonas sp. Principal component analysis (PCA) showed that amongst the bacterial species detected and identified none occurred on all the tested historical materials. The 16S rRNA clone library construction method was successfully used for the detection and diversity determination of bacterial communities inhabiting brick barracks located in the former Auschwitz II–Birkenau concentration and extermination camp in Brzezinka.
Fifty seven taxa of Cyanobacteria and 15 taxa of Chlorophyta were recorded from the exterior of buildings and rock surfaces of monuments in different regions in India. Four cyanobacteria, e.g. Chroococcidiopsis kashayi, Pseudophormidium indicum, Plectonema puteale and Scytonema geitleri, and the green alga Trentepholia abietina var. tenue occur on the sub-aerial habitats throughout the year. In addition, five other green algae: Chlorococcum infusionum, Scenedesmus arcuatus, Trentepholia aurea, Gloeocystis polydermatica and Printzina effusa, and 18 other cyanobacteria taxa of the genera Chroococcus (5), Asterocapsa (1), Cyanosarcina (2), Gloeocapsa (7), Gloeothece (2) and Scytonema (1) occur on the sub-aerial surfaces enduring extreme temperature and desiccation during summer months of the tropics. During the rainy season, the warm and humid climatic regime coupled with availability of moisture supported an additional ten green algae and 29 cyanobacteria in eight and 17 genera, respectively. The green algal genera Klebsormidium, Stichococcus and Trebouxia, which are dominant in temperate regions, did not occur on the sub-aerial habitats in India, however, species of Gloeocapsa, Chroococcus, Chroococcidiopsis, Phormidium, Leptolyngbya, Nostoc, Scytonema, Chlorella and Trentepholia showed global occurrence in similar habitats.
As a result of their unpredictable ability to adapt to varying environmental conditions, microorganisms inhabit different types of biological niches on Earth. Owing to the key role of microorganisms in many biogeochemical processes, trends in modern microbiology emphasize the need to know and understand the structure and function of complex microbial communities. This is particularly important if the strategy relates to microbial communities that cause biodeterioration of materials that constitute our cultural heritage. Until recently, the detection and identification of microorganisms inhabiting objects of cultural value was based only on cultivation-dependent methods. In spite of many advantages, these methods provide limited information because they identify only viable organisms capable of growth under standard laboratory conditions. However, in order to carry out proper conservation and renovation, it is necessary to know the complete composition of microbial communities and their activity. This paper presents and characterizes modern techniques such as genetic fingerprinting and clone library construction for the assessment of microbial diversity based on molecular biology. Molecular methods represent a favourable alternative to culture-dependent methods and make it possible to assess the biodiversity of microorganisms inhabiting technical materials and cultural heritage objects.
The plant growth regulator abscisic acid (ABA) is known to be involved in triggering responses to various environmental stresses such as freezing and desiccation in angiosperms, but little is known about its role in basal land plants, especially in liverworts, representing the earliest land plant lineage. We show here that survival rate after freezing and desiccation of Marchantia polymorpha gemmalings was increased by pretreatment with ABA in the presence of increasing concentrations of sucrose. ABA treatment increased accumulation of soluble sugars in gemmalings, and sugar accumulation was further increased by addition of sucrose to the culture medium. ABA treatment of gemmalings also induced accumulation of transcripts for proteins with similarity to late embryogenesis abundant (LEA) proteins, which accumulate in association with acquisition of desiccation tolerance in maturing seeds. Observation by light and electron microscopy indicated that the ABA treatment caused fragmentation of vacuoles with increased cytosolic volume, which was more prominent in the presence of a high concentration of external sucrose. ABA treatment also increased the density of chloroplast distribution and remarkably enlarged their volume. These results demonstrate that ABA induces drastic physiological changes in liverwort cells for stress tolerance, accompanied by accumulation of protectants against dehydration and rearrangement and morphological alterations of cellular organelles.
Weatherable minerals under many European coniferous forests contain a
network of numerous tubular pores, formed by organic acids exuded by
fungi. We believe that symbiotic mycorrhizal hyphae translocate
dissolved minerals from the isolated micropores directly to their host
plants, bypassing competition for nutrient uptake by other organisms.
The discovery of this pathway challenges current ideas about nutrient
uptake from the bulk soil solution and criteria for critical loads of
acidic deposition on forests.
The materials used on roofs are mainly responsible for the reflection of the incident sunlight and absorption of heat at these surfaces. We investigated the occurrence of fungi and phototrophs, as well as determining the change in color (as L*), solar reflectance and thermal emittance of fiber cement exposed for 5 years in Pirassununga, a rural town in tropical Brazil. Considerable discoloration on the upper, exposed surface was shown to be related to high phototroph (especially cyanobacterial) colonization and reduction in reflectance. The large numbers of fungi detected on the lower, protected surface produced little color change and no reduction in reflectance. Thermal emittance was slightly, though significantly, reduced on the upper surface. The results indicate that, under conditions at this site, after 5 years exposure, phototrophs are more important than fungi in the reduction of reflectance at the exposed surface of fiber cement. This has important implications for cool roofing technology.
Ceramic tiles used in many Catalan Modernist buildings (c.1870 to c.1925) by architects such as Antoni Gaudí, Lluís Domènech i Montaner and Josep Puig i Cadafalch among others are studied scientifically. More than 40 samples, specially selected from all the different types of ceramic tiles used, were studied in detail. XRD and SEM–EDS analyses were carried out to characterize the mineral composition and textural morphology of the paste, interface and glaze of the samples studied. These data will be used as a base for understanding better the decay and behaviour of tiles found in modernist buildings. As most Catalan Modernist buildings are now under restoration, the conservation and replacement of pieces has become an important subject of debate; thus the decay processes are analysed and the restoration protocols exposed.
Pigments of different colours used to polychrome ceramic statues have been characterized using different experimental techniques. The pigments detected in the painting layers belong to the group of natural minerals widely used in antique paintings. The polluted air and the composition of dust and crust on the ceramic surface have been analysed. Environmental pollution has altered the surface of the ceramic sculptures, destroying the polychrome, so that only small parts covered by crust or dust remain. The environment is responsible for transformation of the chemical components of the pigments. The lead compounds minium and hydrocerussite are altered to anglesite, cerussite, hydrocerussite and lead sulphide. Azurite, forming some blue colour, is hydrated to malachite which is green.Atacamite is formed by the transformation of azurite in the presence of the chloride ion from environmental pollution. The environment supplies a variety of organic compounds—mainly alkanes (produced by petrol combustion)—which are responsible for the black coating on the polychrome., which serves as nutrition for microbiological growth.
