Fig 7 - uploaded by Annalaura Casanova
Content may be subject to copyright.
Biopitting on a limestone surface after a biocidal treatment of an endolithic lichen (A), arrow: perithecium. Thin section of Petractis clausa on limestone showing the distribution pattern of voids created by the lichen (B). Interconnections of hyphae in and among the voids (C) (bar = 0,1 mm).
Source publication
This review elucidates current knowledge on the significant role of fungi and lichens in the biodeterioration of stone monuments. The effect caused by many epilithic lichen species in the deterioration of different types of stone has been extensively investigated and demonstrated. Nonetheless, many aspects of the deterioration mechanisms of microco...
Contexts in source publication
Context 1
... deepest thallus reaching 2.7 mm from the surface. According to other authors, hyphae of endolithic lichens can occasionally reach a depth of 19 mm. After the death and the detachment of fruiting bodies pitting formation appears on the stone surface; pits diameter ranges from 0.2 to 1-2 mm, depending on the size of ascocarps of different species (Fig. 7A). These empty pits, also called biopits, that are progressively enlarged by water action (rainfall, water run off, water accumulation) forming pits of major dimensions. These biopits can coalesce and form larger interconnected depressions (called (biotroughs) successively enlarged and the stone surfaces previously colonized by ...
Context 2
... is not properly understood. Moreover, the presence of many hyphal clews arranged in more or less sphaerical voids (c. 20-80 µm in diameter) produced by the dissolution of the substrate, at a certain distance from the surface, were recognized in three endolithic species, Petractis clausa, Encephalographa elisae, and Strigula endolithea, [88,92,93] (Fig. 7B, C). The function of these structures and as much they are widespread in endolithic lichens is unknown. Nevertheless, this should be taken into account in the evaluation of the effects of restoration treatments to kill endolithic lichens that could determine an increase in the water-holding capacity of the stone leaving empty cavities and ...
Similar publications
The Chellah archaeological site in Rabat, listed as a cultural asset since 2012 on UNESCO's World Heritage List, is subject to significant biodeterioration. The aim of this study is to identify the bryophytes that have an important impact on the destruction of the substrate. For this purpose, three prospectionswere carried out in autumn 2014, sprin...
The paper studies the problem of developing the theoretical foundations of the processes of diffusion biodegradation of mineral building materials (cement composites) under the action of aggressive microorganism vital products. The impact of the aggressive environment of microorganisms on the material is taken into account on the basis of Fick’s 2...
The establishment of microorganisms and particularly fungi on rock surfaces, which is favored by humid tropical climates, may accelerate the degradation of historical monuments and buildings and thereby cause the irreversible loss of rich cultural heritage. Therefore, it is urgent to search for new ways to preserve such buildings. The in vitro anti...
This study presents the advances in the field of ZnO/Ag catalysts from the synthesis of hierarchical ZnO nanowires (NWs) decorated with Ag nanoparticles, prepared by a facile solvothermal method at 120°C. It evaluates the photocatalytic efficiency from studying the time reaction of Ag/Zn concentration ratio and the presence of cetyltrimethylammoniu...
Major deteriorations of concrete in sewer networks are observed due to hydrogen sulfide emission. The presence of this gas leads to the decrease of concrete surface pH and then to the development of sulfur-oxidizing bacteria which produce sulfuric acid. Local deteriorations of concrete sewer pipes, based on dissolution-precipitation mechanisms and...
Citations
... CF-PAM detected no chlorophyll fluorescence emission upon MT. Some areas featured the phenomenon of biopitting, which is widely found in stone artefacts [44]. ...
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.
... Recently, numerous studies have concentrated on the biodeterioration of stony cultural heritage [1,2]. Microorganisms can colonize stone monuments in outdoor settings and cause significant stone deterioration [3][4][5]. ...
The biodeterioration of cultural heritage monuments is a worldwide phenomenon, closely linked to the presence of microorganisms and macroorganisms. Microbial colonization leads to physical, chemical damage and esthetic changes. Synthetic polymers, particularly acrylics, are often used to consolidate and protect monuments and artistic stone surfaces. To increase acrylics performances regarding to durability and antimicrobials’ activity, nanoparticles (NPs) were added to polymers. In this study, silver NP was biosynthesized by Malva sylvestris aqueous extract. Furthermore, the in situ method was used for nanocomposite synthesis, which would be simplified the procedure of synthesis. For this, the precursors including the plant aqueous extract, AgNO3 solution and polymer were mixed, and nanocomposite was formed. The morphological characteristics of the obtained nanocomposite were determined using field emission scanning electron microscope (FESEM). The energy-dispersive X-ray (EDX) confirmed AgNPs existence in the composite. Next, the nanocomposite’s antibacterial properties were tested on Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, Cladosporium cladosporioides, Aspergillus niger, and Alternaria alternata. The antibacterial activity of bioengineered nanocomposite compared to acrylic polymer, alone. The results of antimicrobial experiments have shown that the number of bacterial and fungal cells was decreased by 1 logarithm in the polymer, and by 2 to 4 logarithms in the nanocomposite that the antimicrobial effect of latter was notably increased. This study was based on applying this nanocomposite to improve conservation strategies for stony cultural heritage. Further experiments should be performed to evaluate the efficacy of this nanocomposite on outdoor stony model.
... They form overall phototrophic biofilms and gelatinous patinas of different colors (brown, black, green and orange) on surfaces, which can absorb and retain water to withstand long periods of drying. These patinas cause not only aesthetic alteration, but in several cases, microorganisms grow inside the pores and crevices of the substrate, forming mixed communities of algae, cyanobacteria and fungi, leading to microcracks and bio-pitting as they are able to dissolve carbonates [8,[10][11][12][13][14][15][16][17][18]. glasting conservation treatments while minimizing environmental and human health impacts. ...
The study explores the application of natural biocides (oregano essential oil and eugenol, directly applied in solutions or encapsulated within silica nanocapsules) for safeguarding stone cultural heritage from biodeterioration, using green algae (Chlorococcum sp.) and cyanobacteria (Leptolyngbya sp.) as common pioneer biodeteriogens. Core-shell nanocontainers were built for a controlled release of microbicidal agents, a safe application of chemicals and a prolonged efficacy. The qualitative and quantitative evaluations of biocide efficiency at different doses were periodically performed in vitro, after six scheduled intervals of time (until 100 days). The release kinetics of composite biocide-embedding silica nanocapsules were characterized by the UV-Vis spectroscopy technique. Data showed both promising potential and some limitations. The comparative tests of different biocidal systems shed light on their variable efficacy against microorganisms, highlighting how encapsulation influences the release dynamics and the overall effectiveness. Both the essential oils showed a potential efficacy in protective antifouling coatings for stone artifacts. Ensuring compatibility with materials, understanding their differences in biocidal activity and their release rates becomes essential in tailoring gel, microemulsion or coating products for direct on-site application.
... Ortega-Morales et al. (1999) showed that the C/N ratios of biofilm samples collected under different microclimate conditions were close to those of microbial cells, indicating that the main source of organic matter is the biofilm itself [47]. The stimulation of N input promotes carbon assimilation by epilithic microorganisms and increases carbon accumulation on the stone surface by retaining the assimilated carbon in biomass, which is an essential nutrient to support large-scale stone destruction [48]. The positive impact of N deposition on carbon sinks, however, diminished as N saturation increased ( Fig. 2A), potentially due to the decline in pH resulting from N addition. ...
Atmospheric nitrogen deposition may affect the biodeterioration process of stone monuments through direct and indirect pathways, but relevant studies are lacking. Therefore, taking the biologically colonized rocks around the Leshan Giant Buddha (World Heritage - Mixed Property) as the research objects, we studied the effects of multiple nitrogen addition levels (0, 9, 18, 36, 72 kg N hm ⁻² a ⁻¹ ; N0, N1; N2 ; N3; N4) on the bacterial community structure and soil nutrients on the surfaces of stones with four biocolonization types, including naked rock (NR), and lichen (LR), bryophyte (BS) and vascular plant (VS) colonization, to investigate the potential effect of atmospheric nitrogen deposition on the rock weathering of the Leshan Giant Buddha. The results demonstrated that nitrogen addition impacted soil carbon, nitrogen and phosphorus nutrients, as well as bacterial community structure and composition, but the responses to nitrogen input varied among different colonization types. Nitrogen fertilization promoted the accumulation of total organic carbon and total nitrogen in NR and LR, and increased the content of total phosphorus in VS. Bacterial α-diversity decreased with nitrogen addition in NR but increased with nitrogen addition in VS. Nitrogen addition significantly ( R > 0.9, p < 0.01) changed the bacterial community composition in the four biocolonization types, and the changes were dominated by species replacement (contributed to 60.98%, 76.32%, 67.27% and 72.14% for bacterial diversity in NR, LR, BS and VS, respectively). Total nitrogen, dissolved organic nitrogen, dissolved organic nitrogen and total phosphorus were the most important ecological factors affecting bacterial community structure in NR, LR, BS and VS, respectively. Nitrogen addition enriched different bacterial taxa in the four biocolonization types. The results of this study provide basic data for the protection of stone monuments and the formulation of sustainable development strategies under a changing climate.
... The big challenge for restores is represented especially by biopatinas composed of endolithic organisms that penetrate stone surfaces even for a few millimetres, like crustose lichens, cyanobacteria and BF (Ortega-Calvo et al., 1991;Pohl and Schneider, 2002;Crispim and Gaylarde, 2005;Salvadori and Casanova Municchia, 2016;De Leo et al., 2022). Indeed, using the substrate as a shield may decrease the penetration of the active compounds, reducing the expected killing effect and/or hindering the removal of the dead biomass which can feed other colonizers (De los Ríos et al., 2012;Toreno et al., 2018). ...
The prevention and control of biological patinas on outdoor stone monuments represent a demanding challenge for the conservation of cultural heritage also due to some microorganisms, particularly resistant to treatments, such as black meristematic fungi, an eco-physiological group well known for its tolerance to extreme conditions. Even if several methods and eco-friendly products have been proposed as new alternatives, traditional biocides are still far from being completely replaced. Recolonization is a natural process that occurs sooner or later after cleaning. The time that elapses until its occurrence can vary considerably depending on environmental conditions and the used products; unfortunately, the papers describing the effect of treatments over time are rare. This work aims to shed light on the recolonization process of marble surfaces in the ancient monumental cemetery of Bonaria (Cagliari) after nine years from treatments, evaluating the long-term efficiency of two different cleaning methods, namely dimethyl sulfoxide-based gel (DMSO-based gel) and Biotin T (a didecyldimethylammonium chloride-based product-). In this context, the microflora present before treatments and in the following years was assessed by culture-based methods and identified by molecular techniques, with attention on black meristematic fungi, which were used as reference for the most resistant lithobiontic organisms. Different environmental parameters, such as temperature, exposition, dominant winds, and rainfall, were considered, and infrared thermography, portable light microscopy, and image analysis were used. This research evidenced the influence of water availability and lightning in recolonization processes, the transition from the pioneer fungal community versus more resistant black fungal species after Biotin T treatment, and the long-lasting efficiency of the DMSO-based gel. These findings prove that this low-impact method deserves more attention in the conservation of outdoor marble monuments, emphasizing the importance of long-term studies.
... MCF has advantages over other filamentous fungi as it provides physical protection, restricts colony expansion (Ruibal et al., 2009), and can survive under low-nutrient conditions (Tesei, 2022). They are known to colonize stone walls after biocide treatment (Liu et al., 2022) and utilize chemical compounds and mechanical strategies to inhabit specific spaces on surfaces, leading to bio-pitting (Egidi et al., 2014;Salvadori and Municchia, 2016), which can dig into cracks and pores, creating microns to millimeters of bio-pitting on the stone surface during recolonization (Favero-Longo et al., 2011;Liu et al., 2022). These findings support the proposal by Wollenzien et al. (1995) that MCF may have a natural ecological niche in stone environments. ...
Microorganisms naturally colonize rock-based materials in outdoor environments, thereby contributing to their
degradation. Fungi, especially in tropical environments with abundant water and favorable temperatures, play a
significant role in biodegradation. However, many aspects of the microorganism-stone interaction, including
fungal colonization dynamics and the impact of treatment applications, remain unclear. This study conducted a
four-year in-situ evaluation of fungal community dynamics on limestone surfaces in the Temple of the Warriors
at the Chich´en Itza ´ archaeological site in Mexico, focusing on cleaning and treatment using nanoparticles (NPs).
These NPs included zinc oxide (ZnO) and CaZn2(OH)6⋅2H2O (CZ)-based NPs synthesized via sol-gel (CZ-SG) and
mechanochemical methods (CZ-MC), as well as CZ/Ca(OH)2-based products (CZ:Ca-SG). The microbial colonization cover was assessed using colorimetric measurements, and the surface was sampled for fungal community
isolation and identification. The results demonstrated significant impacts of cleaning and nanomaterial
... The mycobiont of lichens, which is always in close contact with the substrate, makes them able to cause deterioration. Bio-deterioration by lichens is, in general, attributed to a combination of physical mechanisms (such as the pressure exerted by the expansion and contraction of thalli, rhizine adhesion, and hyphal penetration) and chemical factors, which include the interaction of carbon dioxide, organic acids, and lichen substances with complex properties [99]. The effects of lichens on the host substrate are shown in Figure 6 [95]. ...
Microbiologically influenced corrosion (MIC) is the process of material degradation in the presence of microorganisms and their biofilms. This is an environmentally assisted type of corrosion, which is highly complex and challenging to fully understand. Different metallic materials, such as steel alloys, magnesium alloys, aluminium alloys, and titanium alloys, have been reported to have adverse effects of MIC on their applications. Though many researchers have reported bacteria as the primary culprit of microbial corrosion, several other microorganisms, including fungi, algae, archaea, and lichen, have been found to cause MIC on metal and non-metal surfaces. However, less attention is given to the MIC caused by fungi, algae, archaea, and lichens. In this review paper, the effects of different microorganisms, including bacteria, fungi, algae, archaea, and lichens, on the corrosion properties of engineering materials have been discussed in detail. This review aims to summarize all of the corrosive microorganisms that directly or indirectly cause the degradation of structural materials. Accusing bacteria of every MIC case without a proper investigation of the corrosion site and an in-depth study of the biofilm and secreted metabolites can create problems in understanding the real cause of the materials' failure. To identify the real corrosion agent in any environment, it is highly important to study all kinds of microorganisms that exist in that specific environment.
... Members of the deleterious acid-producing bacteria of the Acidobacteria phylum were found in all areas of Tel Megiddo, albeit in small quantities (Acidobacteria RSA =0.0015). It is well established that in association with microscopic fungi, Cyanobacteria, one of the most abundant phyla at the site, contributes to the formation of black scabs responsible for esthetic damage (Gaylarde et al., 2007;Salvadori and Municchia, 2016). Finally, members of the Propionibacteriales order, which includes taxa capable of synthesizing propionic acid-an odoriferous, colorless, oily liquid-were also abundant (RSA = 0.08) (Supplementary Table S4A). ...
Introduction
The ancient city of Tel Megiddo in the Jezreel Valley (Israel), which lasted from the Neolithic to the Iron Age, has been continuously excavated since 1903 and is now recognized as a World Heritage Site. The site features multiple ruins in various areas, including temples and stables, alongside modern constructions, and public access is allowed in designated areas. The site has been studied extensively since the last century; however, its microbiome has never been studied. We carried out the first survey of the microbiomes in Tel Megiddo. Our objectives were to study (i) the unique microbial community structure of the site, (ii) the variation in the microbial communities across areas, (iii) the similarity of the microbiomes to urban and archeological microbes, (iv) the presence and abundance of potential bio-corroding microbes, and (v) the presence and abundance of potentially pathogenic microbes.
Methods
We collected 40 swab samples from ten major areas and identified microbial taxa using next-generation sequencing of microbial genomes. These genomes were annotated and classified taxonomically and pathogenetically.
Results
We found that eight phyla, six of which exist in all ten areas, dominated the site (>99%). The relative sequence abundance of taxa varied between the ruins and the sampled materials and was assessed using all metagenomic reads mapping to a respective taxon. The site hosted unique taxa characteristic of the built environment and exhibited high similarity to the microbiome of other monuments. We identified acid-producing bacteria that may pose a risk to the site through biocorrosion and staining and thus pose a danger to the site’s preservation. Differences in the microbiomes of the publicly accessible or inaccessible areas were insignificant; however, pathogens were more abundant in the former.
Discussion
We found that Tel Megiddo combines microbiomes of arid regions and monuments with human pathogens. The findings shed light on the microbial community structures and have relevance for bio-conservation efforts and visitor health.
... In fact, the development of abrasions and lacunae on the painting surface could instead be the result of previous colonization by lichens, which damaged the substrate, probably also making it more susceptible to other degradation processes due to interaction with the external environment [44]. In particular, carbonic acid, which originates from the reaction between carbon dioxide and water retained in the thallus, on coming into contact with the substrate, reacts with its constitutive minerals, performing a chelating action against the basic cations K + , Na + , Mg 2+ and Ca 2+ [45]. ...
This article concerns the diagnostic campaign aimed at analyzing the mural painting representing the iconographic theme of the Deesis of the Church of St. Maria Annunziata, Motta San Giovanni, in the province of Reggio Calabria. In 1951, a flood caused the collapse of the building and the consequent breaking of the apse into two parts. The present study focused on the left side of the apse, hosting the figures of Christ and Mary, in order to plan the best conservation intervention strategy. For this purpose, non-invasive investigations and laboratory analytical methods were conducted in order to characterize the constituent materials and to identify the forms of alteration and degradation present on the surface of the painting. In particular, Raman spectroscopy, optical microscopy, scanning electron microscopy coupled to the chemical analysis by an EDS probe, Fourier-transform infrared spectroscopy and ion chromatography were employed. The results highlighted the presence of a single layer of plaster made with a lime-based binder. The chromatic palette of the painting is characterized by ochres and carbon black mixed with lime to obtain the different shades. Finally, the definition of the nature of the deposits and of the overlaid materials was fundamental in order to identify the best products and methods to restore the readability of the work.
... However, in humid environments, geopolymer and concrete surfaces may be colonized by alkali-resistant bacteria, especially sulphur-oxidizing bacteria (which use sulphur oxidation as source of energy). The bacteria produce acidic compounds (such as sulphane or sulphuric acid) which both chemically degrade both types of material and lower the pH of their surface [29], which allows colonization by other microorganisms, including other species of bacteria [30], algae [31,32], fungi [33], lichens [34] etc., which further damage the surface, both chemically and mechanically. Geopolymers may also be more susceptible to microbial degradation due to their porous (zeolitic) structure [28]. ...
The article summarizes the state of the art in increasing antimicrobial activity and hydrophobic properties of geopolymer materials. Geopolymers are inorganic polymers formed by polycondensation of aluminosilicate precursors in an alkaline environment and are considered a viable alternative to ordinary Portland cement-based materials, due to their improved mechanical properties, resistance to chemicals, resistance to high temperature, and lower carbon footprint. Like concrete, they are susceptible to microbially induced deterioration (corrosion), especially in a humid environment, primarily due to surface colonization by sulphur-oxidizing bacteria. This paper reviews various methods for hydrophobic or antimicrobial protection by the method of critical analysis of the literature and the results are discussed, along with potential applications of geopolymers with improved antimicrobial properties. Metal nanoparticles, despite their risks, along with PDMS and epoxy coatings, are the most investigated and effective materials for geopolymer protection. Additionally, future prospects, risks, and challenges for geopolymer research and protection against degradation are presented and discussed.
