No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Biodegradation of polycyclic aromatic hydrocarbons (PAHs) by native microflora and combinations of white-rot fungi in a coal-tar contaminated soil
Abstract
Four white-rot fungi (Phanerochaete chrysosporium IMI 232175, Pleurotus ostreatus from the University of Alberta Microfungus Collection IMI 341687, Coriolus versicolor IMI 210866 and Wye isolate #7) and all possible combinations of two or more of these fungi, were incubated in microcosms containing wheat straw and non-sterile coal-tar contaminated soil to determine their potential to degrade polycyclic aromatic hydrocarbons (PAHs). Biotic and abiotic controls were prepared similarly and PAH concentrations remaining in each microcosm were determined after 8, 16 and 32 weeks by GC-MS following extraction with dichloromethane. The greatest PAH losses were in the biotic control, compared to small or negligible differences in microcosms inoculated with one or more fungi. These results suggest that in the biotic control native microorganisms colonised the straw added as organic substrate and degraded PAH as an indirect consequence of their metabolism. By contrast, in other microcosms, colonisation of straw by the natural microflora was inhibited because the straw was previously inoculated with fungi. Soil cultures prepared at the end of the experiment showed that though introduced fungi were still alive, they were unable to thrive and degrade PAH in such a highly contaminated soil and remained in a metabolically inactive form.
... Polluted soils contain little organic matter, thus preventing bacterial activity (Siméon et al. 2008). The degrading effect by bacteria has been demonstrated by several studies (Canet et al. 2001;Antizar-Ladislao et al. 2004;Adnan et al. 2014;Al Farraj et al. 2020). ...
The distribution and accumulation of polycyclic aromatic hydrocarbons (PAH) in soil and their impact on three selected species—Lycopersicum esculentum, Cicer arietinum, and Cucumis sativus—have been investigated in areas with high traffic pollution such as the city of Sfax, in the south of Tunisia. PAH were identified in 147 soil samples (0–10 cm). The variation between the physicochemical characteristics of three soils influenced the spatial distribution of PAH. Soil acidity at sites near the Manzel Chaker road can therefore increase the availability of hydrocarbons. Similarly, increasing of organic matter content in these sites can decrease the biodegradation of PAH. The soils near Manzel Chaker road had the highest content followed by those of Tunis road soil. Chrysene, fluoranthene, benzo(a)anthracene, and indeno(1.2.3.cd)pyrene were the most abundant compounds with a content of 49 µg/g, 51 µg/g, 3.8 µg/g, and 45 µg/g respectively. The calculation of the number of germinated seeds by referring to the number of seed germinated, also the root biomass and the shoot elongation of tomato, showed the sensitivity of this species to contamination of Gremda and Manzel Chaker soils. The use of PCA indicated the absence of the impact of fluorene, fluoranthene, naphthalene, and chrysene on the germination of tomato and cucumber and their impact on the aerial part of tomato, but no significant effect on the germination and growth of cucumber was detected. This later has shown resistance to pollution by PAH which can be linked to morphological and genetic aspects.
... Microbial surfactants are the replacement for chemical surfactants due to their high compatibility with the environment and numerous other advantages (Farn 2006;Santos et al. 2019). Biosurfactants are majorly used in the bioremediation of hydrocarbons since they increase the nutrient uptake of hydrocarbons by microbes which reduce the availability of hydrocarbon contaminants in the environment (Canet et al. 2001;Sotirova et al. 2009). ...
Biosurfactants are surface-active amphiphilic substances mainly formed by microorganisms present in the environment, like Bacillus and Pseudomonas. They have various structures like glycolipids, lipopeptides, lipopolysaccharides, and fatty acids. Biosurfactants are readily biodegradable, non-toxic to the environment and exhibit substantial emulsification activities. Biosurfactants also exhibit antioxidant, antimicrobial, anti-aging, cytotoxicity, and anti-inflammatory activities. In this chapter, microbial biosurfactants and their antiviral activities using in vitro and in silico studies are discussed. Biosurfactants show antiviral activity against enveloped viruses since they have hydrophobic and hydrophilic moieties that interact with the envelope proteins of viruses. Surfactin is a lipopeptide that kills herpesvirus, retrovirus, and coronavirus due to its physicochemical interaction with viral membrane and presence of carbon atoms in surfactin’s acyl chain. Biosurfactants from Bacillus sp., Pseudomonas sp., Tolipocladium sp., Streptomyces sp., and Candida bombicola inhibit human immunodeficiency virus, coronavirus, herpes, and influenza viruses. It is predicted that biosurfactants might be the potential inhibitors of SARS-CoV-2. In vitro studies also proved that microbial biosurfactants such as rhamnolipids, surfactin, sophorolipids, glycolipids, lipopeptides, and polysaccharides inhibit porcine parvovirus, pseudorabies virus, Newcastle disease, and infectious Bursal disease viruses. Because of chemically synthesized antiviral drugs’ minimal availability and high toxicity, novel antiviral drugs are needed to manage human viral infections. Biosurfactants could be an alternative to current chemical antiviral drugs due to their low toxicity and compatibility. However, more studies using animal models and human trials have to be conducted to recognize biosurfactants as promising antiviral drugs.KeywordsBiosurfactantsAntiviral ActivityGlycolipidsSophorolipids
Bacillus
Pseudomonas
... Microbe-based bioremediation is one of the most effective and environmentally friendly methods to remediate contaminated soils (Perez et al. 2010;Song et al. 2021). However, bioaugmentation using specialized microbial inocula is susceptible to unfavorable soil environments, which results in failure or a poor effect of remediation on the contaminated soils (Canet et al. 2001). Recently, the use of porous carrier materials to immobilize microbes has been reported to provide protection for microbes from the adverse effects induced by contaminants, unsuitable environmental conditions, and competition with indigenous microbial communities in contaminated sites (Tao et al. 2019;Song et al. 2021). ...
Immobilized microbial technology has been widely used in wastewater treatment, but it has been used less frequently for soil remediation, particularly in sites that are co-contaminated with organic compounds and heavy metals. In addition, there is limited knowledge on the efficiency of remediation and microbial preferences to colonize the immobilized carriers. In this study, biochar immobilized with Sphingobium abikonense was introduced to remediate soils that were co-contaminated with phenanthrene (PHE) and copper (Cu), and the mechanisms of microbial assemblage were investigated. The immobilized microbial biochar maintained a degradation rate of more than 96% in both the first (0–6 d) and second (6–12 d) contamination periods. The addition of biochar increased the proportion of Cu bound to organic matter, and Fe–Mn oxide bound Cu in the soil. In addition, both Cu and PHE could be adsorbed into biochar pellets in the presence or absence of immobilized S. abikonense . The presence of biochar significantly increased the abundance of bacteria, such as Luteibacter , Bordetella and Dyella , that could degrade organic matter and tolerate heavy metals. Notably, the biochar could specifically select host microbes from the soil for colonization, while the presence of S. abikonense affected this preference. The autonomous selection facilitates the degradation of PHE and/or the immobilization of Cu in the soil. These results provide a green approach to efficiently and sustainably remediate soil co-contaminated with PHE and Cu and highlight the importance of microbial preference colonized in immobilized carriers.
Graphical Abstract
... The collected and systematized information became the basis for carrying out research on the preparation of a biological preparation for the simultaneous transformation and detoxification of wood raw materials contaminated with the abovementioned toxic substances. Wheat straw and non-sterile coal-tar contaminated soil to determine their potential to degrade polycyclic aromatic hydrocarbons (PAHs) [51] Podoscypha elegans FTG4 phenanthrene (PHE) and pyrene (PYR) -in-vitro and in-vivo conditions [14] ...
A diverse spectrum of organisms, such as fungi, bacteria, and actinomycetes, can degrade and transform organic matter, including wood, into valuable nutrients. A sustainable economy has the goal of efficiently using waste as raw materials, and in this optic, it uses biological preparations more and more often, supporting the decomposition of lignocellulosic waste. With reference to wood wastes, which are produced in a substantial amount by the forest and wood industry, one of the possibilities to biodegrade such lignocellulosic material is the composting process. In particular, microbiological inoculum containing dedicated fungi can contribute to the biodegradation of wood waste, as well as the biotransformation of substances from the protection of wood, such as pentachlorophenol (PCP), lindane (hexachlorobenzene) and polycyclic aromatic hydrocarbons (PAHs). The purpose of this research was to produce a literature review in terms of the selection of decay fungi that could potentially be used in toxic biotransformation unions. The findings of the literature review highlighted how fungi such as Bjerkandera adusta, Phanerochaete chrysosporium, and Trametes versicolor might be ingredients of biological consortia that can be effectively applied in composting wood waste containing substances such as pentachlorophenol, lindane, and polycyclic aromatic hydrocarbons (PAHs).
... Biosurfactants are used in bioremediation of hydrocarbon. They enhance the growth on hydrophobic surface, increases the nutrient uptake of hydrophobic substrates hence overcoming the poor availability of hydrocarbon pollutants to microorganisms [8][9]. Synthetic surfactants that are currently being used are toxic and difficult to be degraded by microorganisms hence causing damage to the environment. ...
Biosurfactants are amphiphilic compounds produced usually within the cell surfaces of microbes or excreted extracellularly. It contains hydrophobic and hydrophilic parts that reduce surface tension and interfacial tension between individual molecules at the surface and interface respectively. The primary aim of the study was to isolate biosurfactant producing organisms from oil contaminated soil. Through primary and secondary screening methods, it was found that the five isolated organisms were capable of producing biosurfactants. Among these, the organism B, which showed the highest biosurfactant production was selected on the basis of emulsification index and oil displacement activity. The biochemical and molecular characterization of the organism B confirmed that the organism is Aeromonas caviae. The 16S rRNA was sequenced using Sanger dideoxy sequencing method inorder o characterize the biosurfuctant producing strain. The new Aeromonas caviae strain, KVMBS1 isolated from oil contaminated site was deposited in National center for Biotechnology Information (NCBI), Gene Bank, USA and accession number is MT322926.1. From the optimization of production parameters, its optimum temperature was found to be 37 o C and the optimum pH was found to be 7. The best carbon and nitrogen source was found to be kerosene and sodium nitrate respectively.
... Many PAHs threaten public health due to their toxic and carcinogenic properties (Abdel-Shafy & Mansour, 2016) and can cause a food chain imbalance (Foo & Hameed, 2010). Petroleum spills and oil refineries are some of the primary sources of PAH contamination, with the major PAH species being emitted, including fluoranthene and pyrene (Canet et al., 2001;Tang et al., 2005). NAs and phenol are present in the wastewater produced during the waterheavy process for oil extraction from bituminous sands. ...
This research proposes a new method that fuses data from the field and lab-based optical measures coupled with machine learning algorithms to quantify the concentrations of toxic contaminants found in fuels and oil sands process-affected water. Selected pairs of excitation/emission intensities at key wavelengths are inputs to an augmentation neural network (NN), trained using lab-based measurements, that generates synthetic high-resolution spectra. Then, an image processing NN is used to estimate the contaminant concentrations from the spectra generated from a few key wavelengths. The presented approach is tested using naphthenic acids, phenol, fluoranthene and pyrene spiked into natural waters. The spills or loss of containment of these contaminants represent a significant risk to the environment and public health, requiring accurate and rapid detection methods to protect the surrounding aquatic environment. Results were compared with models based on only the corresponding peak intensities of each contaminant and with an image processing NN using the original spectra. Naphthenic acids, fluoranthene and pyrene were easy to detect by all methods; however, performance for more challenging signals to identify, such as phenol, was optimized by the proposed method (peak picking with mean absolute error (MAE) of 30.48 µg/L, generated excitation-emission matrix with MAE of 8.30 µg/L). Results suggested that data fusion and machine learning techniques can improve the detection of contaminants in the aquatic environment at environmentally relevant concentrations.
... Soil microorganisms are widely accepted bioindicators of soil health because they play an imperative part in maintaining soil nutrient, recycling of chemicals, and biodegradation of harmful chemicals, and also act as a biocontrol agent of phytopathogens [13][14][15]. Evaluation and analysis of microbial community of a system provide the active health status of that system, especially soil. Numerous rhizospheric microbes are identified to secrete enzymes such as alkaline phosphatase, proteases, lipases, and dehydrogenases to get essential nutrients via the mineralization of composite polymers [16,17]. ...
Recently, the agriculture system depends on the usage of agrochemicals, which enhance the crop productivity by providing nutrition to plants to meet the global food requirements. A prolonged extensive use of agrochemicals is a principal source of contamination, which persists and biomagnifies in nature and affects the soil characteristics and sustainability. Soil microbes are key components of the agricultural ecosystem to improve crop productivity, and their actions are crucial for maintaining the fertility and health of the soil. Agrochemicals directly or indirectly lead to a shift in the diversity, richness, and evenness of nontargeted beneficial microorganism which orderly decreases the availability of plant nutrition and increases the fate of disease in crops. This chapter focusses on agrochemicals, their classification, and their impact on the soil microflora, especially bacterial and fungal population of cultivated soils.
... The results suggested all the three mesocosms having significant PAHs removal. Degradation of ΣPAHs in mesocosm MC inoculated with mixed culture and mesocosm SC inoculated with S. maltophilia gradually accelerated reaching maximum to 26.67 % Most of the bioremediation studies comprised of in situ microcosm studies (Li et al., 2012;Dave et al., 2014;Niepceron et al., 2013;Canet et al., 2001). However, there are some of the studies reported globally at the mesocosm scale (Ubani et al., 2022;Varjani et al., 2021b;Davis et al., 1993;Kuppusamy et al., 2015;Thavamani et al., 2012;Guazzaroni et al., 2013). ...
The goal of this study was to evaluate the degradation effectiveness of PAHs degrading bacteria at the mesocosm level, including Stenotrophomonas maltophilia (SC), mixed culture (MC), and enriched native microflora (EC) at the mesocosm level. Maximum degradation was found in the mesocosm MC (26.67 %), followed by SC (25.08 %) and EC (18.25 %) after 60 days. Thus, mixed culture and Stenotrophomonas maltophilia could be a game changer in the PAHs bioremediation at the chronically contaminated sites. MiSeq sequencing has revealed dominancy of γ-Proteobacteria, α-Proteobacteria, β-Proteobacteria at class level and Sphingomonadales, oceanospirillales, Rhodothermales at Order level. Families Alcanivoracaceae, Alteromonadaceae, Nocardiaceae, Rhodospirillaceae and genus Stenotrophomonas, Alcanivorax, Methylophaga, Fluviicola and Rhodoplanes were considerably increased which play key role in the PAHs degradation. Dominant bacterial communities have revealed resilience community to enable potential PAHs degradation process in all the mesocosms. To the best our knowledge this is the first ever attempt in PAHs biodegradation study conducted at the mesocosm level mimicking natural environmental conditions. Consequently, this study could be a benchmark against which future progress studies for the policy makers and stakeholders to design appropriate bioremediation study for the historically PAHs polluted contaminate sites.
... Soil microflora helps to form and stabilize soil aggregates and thereby improves the soil's structure, porosity, aeration, and water infiltration (Srivastava et al. 2016). Soil microflora also helps in the bioremediation of anthropogenically contaminated soils and biocontrol of plant pathogens (Canet et al. 2001). ...
Given the dire state of the planet where scarce resources are being exhausted and “waste” is carelessly disposed of, we can find a hero within the concept of the circular economy—a model which aims to achieve a closed loop scenario by recycling the wastes back into the useful economic and ecological flows. Bangladesh, despite her growing population, lacks a dependable institutional waste management system, so the government should apply the concept of circular economy to modify and reconstruct it into a sustainable model. Organic food waste is the major constituent of household waste, containing nutrients and chemicals with too great of an influence on the chemical cycle to simply be disposed of. The current primary waste disposal method followed in Bangladesh is undesirable landfill dumping and such an easily recyclable component like food waste must not follow that path and should be re-circulated back into the loop instead. Currently, there are no comprehensive studies on food waste in Bangladesh to be used for policy guidance. Hence, proper quantification with composition of food wastes is essential to determine the reprocessing potential and provide policy guidance to restructure the existing inefficient waste management system into a sustainable one within the purview of circular economy concept. This chapter attempts to quantify the food waste generation of Bangladesh and explores the various options of available modern technology and methods to recover and reuse food waste. Circularity is the perfect instrument to promote decoupling and achieve sustainability, so its prospect and significance in food waste recycling shall be investigated.KeywordFood waste generationFood waste recyclingCircular economyBangladesh
... Soil microflora helps to form and stabilize soil aggregates and thereby improves the soil's structure, porosity, aeration, and water infiltration (Srivastava et al. 2016). Soil microflora also helps in the bioremediation of anthropogenically contaminated soils and biocontrol of plant pathogens (Canet et al. 2001). ...
The chapter analyses the short-run and long-run effects of international trade on the environment. For this purpose, the bounds testing method to cointegration is applied to a small island country setting of Mauritius and over the period 1980–2018. The result shows that that trade has adversely impacted on the environment. In addition to that, higher economic growth is as well observed to generate higher CO2 emission. Furthermore, the CUSUM and CUSUM square confirm the stability of the model for Mauritius.KeywordsTradeCO2 emissionsARDLMauritius
... The superior properties of biosurfactants include high biodegradability, low toxicity, ecological acceptability, and production from cheaper substrates (Nitschke and Pastore, 2004). Biosurfactants are widely used in hydrocarbon bioremediation field since they can enhance the growth on hydrophobic surface and can increase the nutrient uptake of hydrophobic substrates thereby overcoming the poor availability of hydrocarbon contaminants to microorganisms (Canet et al., 2001;Sotivora et al., 2009). Extracellular excretion of biosurfactants by bacteria has been reported by many studies (Pornsunthorntawee et al., 2007;Kumar et al., 2008;Thavasi et al., 2008). ...
Objectives
This study was aimed to isolate and identify the biosurfactant producing marine bacterium from petroleum hydrocarbons contaminated sediments by 16S rRNA gene sequencing.
Methods
Soil sample was enriched with diesel (2%) as the sole source of carbon in minimal salt medium for 3 weeks at 28°C±2. Enriched sample was plated on nutrient agar and the organisms are selected based on the colony morphology. Biosurfactant producing efficiency of the isolates were assessed using blood haemolysis, oil displacement test, microplate assay or drop collapse test and emulsification activity. Identification of the efficient biosurfactant producing isolate was done by gram staining and biochemical tests. Molecular characterization was done using 16S rRNA gene sequencing.
Results
Totally seven isolates were selected based on colony morphology and among them, the isolate ADY2b was able to reduce surface tension significantly in the oil displacement test and also formed a stable emulsion. The emulsification index (E24) had shown a promising result of 58.33%. The isolate ADY2b was a motile, gram negative rod shaped bacterium and positive for catalase and oxidase. Sequence alignment of the 16S rRNA of the ADY2b strain and database search revealed 98% similarity to Pseudomonas mendocina by BLAST analysis.
Conclusion
Seven bacteria were isolated from petroleum hydrocarbon contaminated sediments. Strain ADY2b had shown promising results on the production of biosurfactants and it may be capable of increasing the bioavailability of poorly soluble petroleum hydrocarbons. The isolate Pseudomonas sp. ADY2b obtained in the study had potential to be used in oil degradation purposes.
... The level of PAHs in soils in urban areas is approximately 2-10 times higher than in rural areas [1]. Many former industrial sites occur near city centers and have high land value, therefore there is a need to purify the soil to meet development requirements and increase the attractiveness of those sites [4]. PAHs are highly hydrophobic, immobile, and stable chemical structures, which can be rapidly absorbed by soil particles which results in their persistence in the environment and difficulties in removing them [1,5]. ...
The main objectives of this study were to isolate bacteria from soil chronically contaminated with polycyclic aromatic hydrocarbons (PAHs), develop an autochthonous microbial consortium, and evaluate its ability to degrade PAHs in their native contaminated soil. Strains with the best bioremediation potential were selected during the multi-stage isolation process. Moreover, to choose bacteria with the highest bioremediation potential, the presence of PAH-degrading genes (pahE) was confirmed and the following tests were performed: tolerance to heavy metals, antagonistic behavior, phytotoxicity, and antimicrobial susceptibility. In vitro degradation of hydrocarbons led to the reduction of the total PAH content by 93.5% after the first day of incubation and by 99.22% after the eighth day. Bioremediation experiment conducted in situ in the contaminated area resulted in the average reduction of the total PAH concentration by 33.3% after 5 months and by over 72% after 13 months, compared to the concentration recorded before the intervention. Therefore, this study implicates that the development of an autochthonous microbial consortium isolated from long-term PAH-contaminated soil has the potential to enhance the bioremediation process.
... The selected tobacco waste (TW, Tobacco factory, Wuhan, China) and sawdust waste (SW, Timber mill, Wuhan, China) were Energies 2020, 13, 6202 3 of 10 crushed and sieved as subsequent experimental materials (with a particle size distribution of 0.125-0.25 mm). Dichloridemethane (analytical grade, Aladdin reagent, Shanghai, China) was used as solvent for bio-oil collection [17]. ...
The condensation-collection and quantitative analysis of bio-oil limit its component investigation and utilization. In order to find a convenient method for the analysis of bio-oil, the present study conducted an attempt for bio-oil quantitative analysis with the addition of internal standards before pyrolysis. Based on their good thermal stability, phenethyl acetate and naphthalene were selected as standards in the study and experiments were carried out to compare the effects of two added modes (adding into the biowaste before pyrolysis or adding into bio-oil after pyrolysis) on the bio-oil analysis. The results showed that both phenethyl acetate and naphthalene were mainly volatilized under testing conditions, which could be transferred into the oil with the volatile matters during biowaste pyrolysis. Through the co-pyrolysis experiments of the internal standards with lignin and cellulose, almost no interactions were found between the internal standards and such components. Furthermore, adding these standards before pyrolysis hardly affected the properties of noncondensable gas and biochar from the used biowaste samples (tobacco and sawdust waste). Compared with the bio-oil analysis results via traditional methods by adding standards into the bio-oil after pyrolysis, the results regarding the component distribution characteristics of the bio-oil were similar using the proposed method through the addition of standards before pyrolysis. Considering adequate mixing of the added standards (before pyrolysis) in the generated bio-oil, the proposed method could partly help to avoid inaccurate analysis of bio-oil components caused by incomplete collection of the pyrolytic volatiles.
... Indeed, the white-rot basidiomycetes S. commune was present one year after inoculation. It had been reported earlier that white-rot fungi, such as Phanerochaete chrysosporium, Trametes versicolor, Pleurotus ostreatus, and many more need an added carbon source to survive in soil (Morgan et al., 1993;Canet et al., 2001). As best carbon source, hemicellulose-containing substrates, like chopped wheat straw, were reported (Hultgren et al., 2010). ...
Radioactive contamination resulting from major nuclear accidents presents harsh environmental conditions. Inside the Chernobyl exclusion zone, even more than 30 years after the accident, the resulting contamination levels still does not allow land-use or human dwellings. To study the potential of basidiomycete fungi to survive the conditions, a field trial was set up 5 km south-southwest of the destroyed reactor unit. A model basidio-mycete, the lignicolous fungus Schizophyllum commune, was inoculated and survival in the soil could be verified. Indeed, one year after inoculation, the fungus was still observed using DNA-dependent techniques. Growth led to spread at a high rate, with approximately 8 mm per day. This shows that also white-rot basidiomycetes can survive the harsh conditions in soil inside the Chernobyl exclusion zone. The unadapted fungal strain showed the ability to grow and thrive in the contaminated soil where both stress from radiation and heavy metals were present.
... Although, the results state the ability of the indigenous soil microorganism in the degradation of PAHs, the provision need of the favorable conditions and external nutrients might also promote the heterogeneous non PAHs degrading microorganisms, which creates a competition with potential degraders, thereby limiting the degradation rates Bioremediation of soil contaminated by hydrocarbons with the combination of three technologies: bioaugmentation, phytoremediation, and vermiremediation (Rodriguez-Campos et al., 2019; Sayara et al., 2011). The results statistically manifest the reduction in the degradation of BaP when compared to Phe in all the strategies (Fig. 1b), which is explained by rapid sorption of BaP to the nanopores of SOM (Canet et al., 2001;Cavalca et al., 2002). Additionally, a significant degradation of co-contaminants, i.e., phenols, was observed in all the strategies except in abiotic condition. ...
Bioremediation of polycyclic aromatic hydrocarbons (PAHs) in soil matrix is often arbitrated by the presence of soil organic matter (SOM). The present study focuses on determining the effect of the soil organic content on the mycoremediation of two model PAHs, phenanthrene (Phe) and benzo(a) pyrene (BaP) through microcosm studies. On comparing various microcosm strategies, a maximum degradation of Phe (99%) and BaP (48.5%) in soil bioaugmented with Pleurotus dryinus IBB 903, followed by, biostimulation with the degradation of Phe (89.9%) and BaP (24.8%) were noted. On relating the degradation pattern with lignolytic enzyme cocktail production, a laccase activity of 108 U/Kg at day 21, aryl alcohol oxidase (411 U/Kg) and manganese peroxidase (52.2 U/Kg) at day 14 along with lignin peroxidase (481 U/Kg) at day 21 were noted in fungal augmented soils, which were comparatively higher than levels observed in the bio-stimulation. Investigating the impact of different concentration of SOM (3–12%), a maximum remediation of Phe by 100% at 9% SOM in days 28 and 58.19% for BaP at 12% SOM, respectively was exhibited. Further, the biosorption effect of PAHs in abiotic condition showed a positive correlation with the increase in SOM, with a maximum adsorption of 3.78% Phe, and 6.93% BaP. The results support that the nominal adsorption ability of SOM, and helps in enhancing the microbial growth, thereby improving their degradation potentials, when less than 6% of SOM was utilized. Overall, this work establishes the critical role of organic matter in the soil with reference by simultaneous stimulation and degradation capability in complete PAHs remediation.
... It was found that the dissipation of total petroleum hydrocarbons (TPH) and the amounts of cultivable TPH, alkane, and PAH-degrading microorganisms were higher for biostimulation than for bioaugmentation. Similarly, Canet et al. [118] demonstrated that fungal inoculation, including four well-known PAH-degrading microorganisms (P. chrysosporium IMI 232175, Coriolus versicolor IMI 210866, Pleurotus ostreatus IMI 341687, and Wye isolate #7) in a mixture composed of non-sterile, coal-tar-contaminated soil and wheat straw, was unsuccessful in improving PAH removal. ...
Bioremediation of contaminated soils has gained increasing interest in recent years as a low-cost and environmentally friendly technology to clean soils polluted with anthropogenic contaminants. However, some organic pollutants in soil have a low biodegradability or are not bioavailable, which hampers the use of bioremediation for their removal. This is the case of polycyclic aromatic hydrocarbons (PAHs), which normally are stable and hydrophobic chemical structures. In this review, several approaches for the decontamination of PAH-polluted soil are presented and discussed in detail. The use of compost as biostimulation- and bioaugmentation-coupled technologies are described in detail, and some parameters, such as the stability of compost, deserve special attention to obtain better results. Composting as an ex situ technology, with the use of some specific products like surfactants, is also discussed. In summary, the use of compost and composting are promising technologies (in all the approaches presented) for the bioremediation of PAH-contaminated soils.
... The content of lignin in the plant varies from 10 to 30% depending on the source of the plant (Chatel and Rogers 2013). The physiological importance of lignin biodegradation is the destruction of the matrix that is formed by it to release hemicelluloses and cellulose so that the microorganism can gain better access to those real substrates for obtaining energy (Canet et al. 2001). Thus, lignin degradation is an important aspect of carbon recycling in the biosphere, which is facilitated by lignin-degrading microorganisms (Bozell and Petersen 2010). ...
The production of enzymes involved in lignin degradation (laccase, ligninase), carbon cycling (β-glucosidase), and phosphorous cycling (phosphomonoesterase) by white rot fungi (Pleurotus sajor-caju) was studied. In the presence of chlorpyrifos, carbofuran, and their mixture, laccase activity was highest on the 7th day, i.e., 192.5 ± 0.31 U ml− 1, 213.6 ± 0.31 U ml− 1, and 164.6 ± 0.31 U ml− 1, respectively, compared to the control which produced maximum laccase on the 14th day (126.9 ± 0.15 U ml− 1). Phosphomonoesterase activity in the presence of chlorpyrifos, carbofuran, and their mixture was 31.5 ± 0.25, 24.1 ± 0.15, and 29.2 ± 0.35 µg PNP min−1 ml−1, respectively, which was more than the control on the 21st day (11.63 ± 0.21 µg PNP min−1 ml−1). β-Glucosidase production increased with the days of incubation in the presence of pesticides than in the control. β-Glucosidase activity on the 21st day in the presence of chlorpyrifos, carbofuran, and their mixture was 32.4 ± 0.1, 24.2 ± 0.3, and 28.4 ± 0.25 µg PNP min−1 ml−1, respectively, as compared to control (15.3 ± 0.6 µg PNP min−1 ml−1). Thus, chlorpyrifos, carbofuran, and their mixture were found to have a positive effect on the production of laccase, β-glucosidase, and phosphomonoesterase by P. sajor-caju, which can use these pesticides as a source of their nutrition, thereby improving the health of pesticide-polluted soils.
... Microorganisms play an instrumental role in pursuing biodegradation of harmful chemicals and pollutants released because of anthropogenic activities. They also act as biocontrol agents for phytopathogens in agricultural soils (Canet et al., 2001). Soil microorganisms have thus been widely accepted as the bioindicators of soil health (Nielsen and Winding, 2002). ...
Modern agriculture fundamentally relies on an extensive use of agrochemicals to enhance crop productivity by controlling harmful pests, pathogens, and undesirable weeds. However, currently, we have reached a stage where several threats are emerging on food security, human and environmental health, maintenance of ecological balance, and conservation of the soil biodiversity. Long-term unbalanced use of agrochemicals may lead to community shift of beneficial microorganisms with dangerous consequences such as the development of antimicrobial resistance. Agrochemicals usage in farming systems may adversely influence soil microorganisms that are mainly involved in nutrient cycling processes, such as nitrogen fixation, phosphorus solubilization, and other essential nutrient biotransformation. The recent report established that some agrochemicals reduce biochemical reaction and activities of soil enzymes that are key indicators of soil microbiological health. This chapter focuses on the effects of applied agropesticides on soil microbiological and biochemical health attributes under different cropping systems.
... Composting has been demonstrated to be effective in biodegrading polycyclic aromatic hydrocarbons (PAHs) (Canet et al. 2001;Potter et al. 1999), chlorophenols (Laine et al. 1997), polychlorinated biphenyls (Block 1998), explosives (Gray 1999) Poly (cis-1,4 -isoprene) Ibrahim et al. (2006) and petroleum hydrocarbons (Namkoong et al. 2002) at the laboratory and/or fieldscales. Compositing and addition of compost act as stimulants of natural attenuation (Kastner and Miltner 2016). ...
A Bioremediation process includes bioinjection, bioaugmentation and phytoremediation and relies on the management of suitable plants and soil microorganisms, either natural or tailor made, that can degrade, sequester, or remove environmental contaminants and are capable of catabolizing the contaminants. Actinobacteria are present in high concentration in soil and use humic acid that helps in recycling substances in nature. They are nonmotile, filamentous, anaerobic bacteria, belonging to order Actinomycetales, present in soil, having amazing metabolic versatility and mechanism to clean up the hazardous pollutants. Actinobacteria are also present under extreme conditions such as high temperature, low moisture, nutrient starvation and producing biosurfactants and speeding up the reaction for biological oxidation and biodegradation of the pollutants. These bacteria have resistance mechanisms for producing as superoxide dismutases, efflux transporters and metal binding proteins. They cause degradation of herbicides, pesticides (organochlorine-lindane), heavy metals, chromium (VI), petrochemicals, nitroaromatics, 2,4,6 trinitrotoluene (TNT), tannery wastes and aromatic compounds. Bioremediation, an appropriate remedy, depends on the nature of contaminants. If the contaminants are susceptible to biodegradation by the site organisms (without the need for human intervention) is known as intrinsic bioremediation. Alternatively, relevant organisms can be added i.e. Engineered bioremediation. In both conditions rate of bioremediation depends on, the type and concentration of contaminant, the microbial community, and the subsurface hydro- geochemical conditions. New niches and extreme micro ecosystems, in terms of temperature, salt concentration, and pH, should be explored to identify and locate new microorganisms able to deal with heavy metals, hydrocarbons, chlorinated compounds and in general, all pollutants affecting soil and water. Therefore bioremediation is useful for large scale application on heterogeneous environment such as ground water, soil sludge and industrial wastes.
... PAH concentration determined by GCMS after 8, 16, and 32 weeks. Results revealed native microorganisms colonized straw and degraded PAH while introduced fungi remained inactive (Canet et al. 2001). Two crude oildegrading fungal strains Penicillium sp. ...
There is a worldwide concern regarding soil pollution caused by contamination of petroleum hydrocarbon, released during oil processing or production. Once a spill occurs, it disturbs the marine and freshwater ecosystem and greatly threatens human health. It usually requires complex technologies to remove it from soil. Petroleum hydrocarbons contain a range of chemicals which are extremely toxic and carcinogenic in nature. Although physical or chemical methods are widely employed for remediation, numerous studies revealed that bioremediation is a sustainable approach. Bioremediation is often preferred as clean and carbon-neutral solution. This review aims to provide series of sustainable solution for petroleum hydrocarbon degradation without exploiting the environment as well as opportunity to reuse treated media. Integrated and enhanced bioremediation technologies are more effective than natural degradation of petroleum hydrocarbons in terms of shorter time period and percent removal efficiency. It comprehensively illustrates bioremediation assisted with bacteria, fungi, and algae either by integrated technologies or by enhancing the process. Most recent application methods of petroleum hydrocarbon bioremediation (in situ and ex situ) are also reported. There is dire need to explore different cost-effective biotechnological resources for degradation of petroleum hydrocarbon by the screening of novel microbial strains or by the creation of genetically engineered bacteria to survive in harsh environment.
... Furthermore, the soil microflora positively affects physical properties of the soil such as its structure, porosity, aeration, and water infiltration through the formation and stabilization of soil aggregates (both macro-and microaggregates) (Zhong and Cai, 2007;Srivastava et al., 2016). The soil microbial community also plays pivotal roles in the execution of ecofriendly processes such as bioremediation of contaminated soils which are developed due to anthropogenic factors (Canet et al., 2001) and biocontrol of plant pathogens. ...
Under the global scenario of burgeoning population it is imperative to ensure food security by increasing crop production. There is increasing concern, however, that agricultural intensification leads to large-scale ecosystem degradation and loss of productivity by hampering the soil health in the long term. Further, application of excessive fertilizers and pesticides to improve crop production have negative environmental implications including soil degradation, enhanced greenhouse gas emissions, accumulation of pesticides and decline in the availability and quality of water. It is important to develop a sound understanding of the fate of a pesticide, particularly in soils where the microbial communities interact with plants to accomplish functions supporting a number of ecosystem services. Synthetic fertilizer application begins the destruction of soil biodiversity by suppressing the role of nitrogen fixing bacteria and enhancing the role of everything that feeds on nitrogen. These feeders then amplify the decomposition of organic matter and humus. As organic matter decreases, the physical structure of soil changes. These changes lead to modulations in various associated soil physiological processes. However, there are several contradicting reports on above mentioned negative impacts of pesticides and synthetic fertilizers. Therefore, the present chapter intends to understand interaction of pesticides and synthetic fertilizers with soil microbiome and soil processes.
... Thus, the biological degradation of lignin must occur through the activity of extracellular enzymes. The physiological importance of lignin biodegradation is the destruction of the matrix it forms, so that microorganisms can gain access to the real substrates hemicellulose and cellulose [5], from where they obtain energy. ...
This chapter contains sections titled: Introduction Ligninolytic Enzymes Sources of Ligninolytic Enzymes Production of Ligninolytic Enzymes Purification of Ligninolytic Enzymes Potential Applications of Ligninoytic Enzymes Outlook
... The PAHs comprising anthracene, phenanthrene, and pyrene were extracted through LLE and SPE followed by GC-MS analysis which showed degradation by 54%, 42% and 27% respectively [113]. Hydrocarbon degradation potential of white rot fungi isolated from coal-tar contaminated soil is also reported in which various PAHs were determined through GC-MS analysis [109]. One of the very interesting features of GC-MS analysis is its capability to detect at ultra-trace levels of analytes. ...
Bioremediation is a familiar process involving actions of microorganisms on the pollutants present in environmental matrices. Monitoring the fate of petroleum hydrocarbons present as contaminants in environmental samples is a retrospective approach to assess the progress of biodegradation process. Chemical analysis is essential in the determination of hydrocarbons at various stages of the experiment. Pervasive research in this area has involved the use of popular analytical tools such as chromatography and spectroscopy. This review focuses on the significance of analytical chemistry in monitoring of bioremediation experiments. The discussions present a comprehensive account of the analysis plan, deviations and critical description of the involved approaches for determination of different hydrocarbons present in petroleum-contaminated soils. Various sample pre-treatment methods such as liquid-liquid, solid-phase, Soxhlet, pressurized fluid extraction etc. have been discussed. Use of chromatography, spectroscopy and other hyphenated platforms is also discussed to expand the prevalent scenario of analysis in bioremediation studies.
... Mnoho autorů uvádí, že využití hub bílé hniloby, zejména houby Pleurotus ostreatus nebo jiných zástupců basidiomycet (rody Irpex, Trametes, Phanerochaete, Ganoderma) jsou velice perspektivní pro jejich možné využití v mykoremediační praxi (Canet et al., 2001;Li et al., 2012;García-Delgado et al., 2015). ...
Persistentní organické polutanty (dále jen POPs) patří k velmi rizikové skupině kontaminujících sloučenin, běžně se nacházejících v životním prostředí a hromadících se v půdě. Zde mohou negativně působit na všechny živé organizmy, z půdy mohou být transportovány do potravního řetězce a ohrožovat zdraví zvířat a lidí.
Hlavním cílem předkládané metodiky je zhodnotit účinnost substrátů vyrobených z upravených lignocelulózních materiálů s prorostlým myceliem hub hlívy ústřičné (Pleurotus ostreatus (Jacq.) P. Kumm) a pohárovky obecné (Crucibulum laeve Huds.) na degradaci perzistentních organických polutantů přítomných v kontaminované půdě. Tato bioremediační metoda je označována jako mykoremediace. Jako zástupce POPs v půdě bylo vybráno 16 základních polycyklických aromatických uhlovodíků (PAU), které jsou dle US EPA (United States Environmental Protection Agency) označovány za prioritní organické polutanty životního prostředí. Vyplozené substráty z hub jsou v rámci mykoremediace kontaminované půdy testovány společně s rostlinami kukuřice seté (Zea mays L.). Dalším cílem je poskytnout výrobcům a pěstitelům hub návod k přípravě substrátů pro pěstování vybraných druhů hub vhodných pro mykoremediace půdy a uvést ověřený postup na využití substrátů pro mykoremediace půdy kontaminované PAU. Metodika je aplikovatelná i jako bioremediační metoda in situ přímo na kontaminované zemědělské půdy. Metodika je vhodná pro společnosti zabývající se dekontaminacemi PAU v půdě a pro podniky, které kladou velký důraz na biologické, environmentálně šetrné a ekonomicky přijatelné způsoby odstranění těchto zdravotně rizikových a potenciálně karcinogenních látek ze zemědělské půdy.
... Data from the literature suggests that an important initial step in the degradation of high molecular weight hydrocarbons is the action of fungal extracellular enzymes (oxidoreductases, laccases and lignin peroxidases) (Anderson and Cairney, 2004;Balaji et al., 2014;Cerniglia, 1993; into the cell, as is the case for bacterial degradation (Scullion, 2006). The smaller compounds can then undergo further metabolism by other fungi and/or bacteria (Canet et al., 2001;Silva et al., 2009;Smit et al., 1999). ...
The contamination of soil with petrogenic hydrocarbons represents a significant human health concern as a result of the carcinogenic and mutagenic properties of a number of compounds commonly found in petroleum products such as polycyclic aromatic hydrocarbons (PAHs). Although it is known that soil fungal communities play an important role in the degradation of highly branched petroleum hydrocarbons and high molecular weight PAHs, little information is available regarding the impact of petrogenic contamination on the structure and diversity of the fungal community and the impact of soil type on the fungal community response. Here, the aim of this study was to evaluate the impact of petrogenic contamination on fungal communities in two soil types. In sandy soils, the most contaminated test pit had the highest fungal diversity. Fungal profiles were dominated by species from the class Eurotiomycetes and included the well-known hydrocarbon-degrading species of Aspergillus and Eurotiales. The dominance of these species did not change with contamination concentration, suggesting a level of adaptability to multiple carbon sources. There appeared to be no correlation between fungal species diversity and contaminant concentration in the clayey soil. Similar dominant fungal species were identified in the clay and sandy soils, all of which were part of the phylum Ascomycota. The clayey soils had a higher species diversity and range-weighted richness compared to sandy soils, which may be a result of the pore connectivity theory i.e. as a result of low water connectivity in soils the formation of diverse communities is promoted through creation of microhabitats.
... The maximum PAH losses were in the biotic control. The results suggested that in the biotic control, inhabitant organisms populate the straw as organic substrate and degraded PAH as an incidental result of their metabolic process (Canet et al., 2001). P. chrysosporium has the ability to degrade and mineralize a wide variety of aromatic, alicyclic, and aliphatic chemical waste, such as petroleum hydrocarbons, PAHs, dioxins, PCBs, herbicides, pediculicide, wood preservatives, chlorinated aliphatic solvents, detergent components, azo dyes, and nitroaromatics (Leung et al., 2005). ...
Polychlorinated biphenyls (PCBs) are organic compounds that find a large number of applications at industrial level. Due to their low bioavailability and stability, they are persistent in the environment and also impose deleterious effects on animals and plants. Degradation of these compounds by microbes is a cost-effective strategy to remove these hazardous compounds from the environment and is also receiving greater attention. A number of microbes belonging to phylum Actinobacteria, Ascomycota, Bacteroidetes, Basidiomycota Firmicutes, and Proteobacteria of the genera Achromobacter, Arthrobacter, Aspergillus, Bacillus, Janibacter, Janthinobacterium, Ochrobactrum, Paenibacillus, Pseudomonas, Rhodococcus, Shigella, Sphingobium, Sphingomonas, Stenotrophomonas, Talaromyces, Trametes, and Williamsia have been reported to degrade PCBs. There are many reports on the study of the degradation pathways used by the microbes to degrade these compounds as well as the detailed enzymatic steps involved. Further, the catabolic genes (bph) responsible for the degradation in diverse microbes have been studied, which shows a greater diversity in the arrangement of these genes. Also, bph genes have been cloned from different bacterial strains. The study of biodegradation is a complex process and requires the combined study of microbial ecology, biochemistry, and genetic engineering with the aim that the efficient strains may be improved for enhanced degradation and to understand how microbes acquire novel degradation capabilitie
... The impact of compost or composting that are free from pathogens on microbial enzyme production is effective as it serves as substrate which promotes microbial growth. Fungi especially the Basidiomycota group which contains fungi genera have been well reported as effective degraders of lignin through their enzymes such as lignin or manganese peroxidases, catalases, laccases or Cytochrome P450 clans and these enzymes are usually secreted extra-cellularly on their substrates, using those substrate as composts for soil amendment promote bioremediation (Eggen, 1999;Canet et al., 2001;Lau et al., 2003;Asemoloye et al., 2017c. More specifically, these lignin degrading enzymes often times contains necessary complex arrays and mechanisms for degradation of some soil pollutants such as PAHs. ...
Bioremediation (the use of living organism, part or their products) has been reported to be an environmental friendly
and cheap remediation method which is applicable in large and small scale but, the major problem facing this mechanism
is the establishment of a particular biological entity in a heavily polluted soil. The soil supplementation/amendment
during bioremediation was suggested to alleviate such difficulty, compost supplements role in bioremediation is majorly
‘biostimulatory’ a term used to explain the addition of nutrients for effective and active biological activities. Compost
supplements have been a commonly used practice in agricultural practices for ages for enhancement of soil fertility and
productivity but it is now known that this practice also enriches the microbial population in soil which promotes soil
remediation as they act upon the organic waste to release its nutrients. This practice as well have been reported to enhance
biological degradation, mineralization or extraction of a pollutant for clean-up/remediation of a polluted soil. Today,
bioremediation mechanism which combines action of two or more organisms have been gaining more interests,
application of soil amendments in such setting may serve as fuel to run the system feeding both entities the nutrients, creates environment conducive for their survival and enhances tolerance as well as responses. In this chapter, we gave
accounts of biostimulatory and bioaugmentation mechanisms brought about by soil amendment using composts, we considered different examples and their impacts on soil bioremediation mechanisms.
... Most research work was on the uptake and/or metabolism of a single PAH contaminant, and very few reported the situation with two or more PAHs. In nature, it is common to have a mixture of PAH contamination, interacting with each other (Canet et al. 2001;Tang et al. 2005). However, the possible stimulatory, antagonistic, and competitive uptake and metabolism of the combined PAHs received little exploration (Dean-Ross et al. 2002;Herwijnen et al. 2003;Lei et al. 2007). ...
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic pollutants, primarily generated during the process of incomplete combustion, extraction, exploitation and transportation of fossil fuel. PAHs are environmental and human health hazards due to recalcitrance, toxicity, carcinogenic and mutagenic nature. Therefore, a sustainable cleanup approach is required for the removal of PAHs from contaminated sites. Efficiency of biosorption process for the removal of toxic pollutants has been thoroughly studied in the past. This chapter focuses on the application of microalgae green biosorbents for the removal of PAHs. Characteristics, environmental fate of PAHs and algal biochemistry are summarized. Algae cell structural constituents act as specific binding sites for removal of pollutant, and share enzymatic systems similar to bacteria. Major enzymes responsible for biodegradation of PAHs are described. Immobilization and co-culture technique for enhance biosorption are discussed
Degradation, detoxification, or removal of the omnipresent polycyclic aromatic hydrocarbons (PAHs) from the ecosphere as well as their prevention from entering into food chain has never appeared simple. In this context, cost-effective, eco-friendly, and sustainable solutions like microbe-mediated strategies have been adopted worldwide. With this connection, measures have been taken by multifarious modes of microbial remedial strategies, i.e., enzymatic degradation, biofilm and biosurfactant production, application of biochar-immobilized microbes, lactic acid bacteria, rhizospheric-phyllospheric-endophytic microorganisms, genetically engineered microorganisms, and bioelectrochemical techniques like microbial fuel cell. In this review, a nine-way directional approach which is based on the microbial resources reported over the last couple of decades has been described. Fungi were found to be the most dominant taxa among the CPAH-degrading microbial community constituting 52.2%, while bacteria, algae, and yeasts occupied 37.4%, 9.1%, and 1.3%, respectively. In addition to these, category-wise CPAH degrading efficiencies of each microbial taxon, consortium-based applications, CPAH degradation–related molecular tools, and factors affecting CPAH degradation are the other important aspects of this review in light of their appropriate selection and application in the PAH-contaminated environment for better human-health management in order to achieve a sustainable ecosystem.
Graphical Abstract
This study was amid to isolate soil fungi from agriculture soil and study their roles in the biodegradation of carbendazim fungicide at different concentrations were explored for two periods of incubation. Results showed the highest degradation rates of carbendazim at 4 part per million (ppm) concentration were observed by using single culture of Aspergillus niger (69.66% and 99.96% after 10 and 20 days, respectively).In the mixed cultures of Exerohilum sp., Fusarium sp., and A. niger, the maximum degradation rate (98.34%) was achieved at the same concentration after 10 days. The mixed culture of Exerohilum sp. and Fusarium sp. demonstrated the highest degradation rates of (92.14% and 55.74%) at 8 and 12 ppm concentrations, respectively, after 10 days of incubation. Aspergillus niger (وكانت 69.66 و % 99.96 التتابع على)% بعد 10 و 20 الفطريات من المكونة الفطرية المزرعة اما الحضن. من يوم A. niger Exerohilum sp. و Fusarium sp., تكسير نسبة اعلى سجلت فقد وبلغت حيوي (98.34%) بعد 10 سجلت السابق. التركيز ولنفس الحضن من ايام للفطرين المختلطة المزرعة Exerohilum sp. و Fusarium sp. بلغ حيوي تكسير نسبة اعلى سجلت فقد 92.14) و % 55.74 بتركيز)% 8 و 12 بالمليون جزء الحضن. من ايام عشرة بعد الي التو على المفتاحية الكلمات : مختلطة. الت عز الحيوي، التربة،التكسير فطريات ايم، كاربندز
This study was amid to isolate soil fungi from agriculture soil and study their roles in the biodegradation of carbendazim fungicide at different concentrations were explored for two periods of incubation. Results showed the highest degradation rates of carbendazim at 4 part per million (ppm) concentration were observed by using single culture of Aspergillus niger (69.66% and 99.96% after 10 and 20 days, respectively).In the mixed cultures of Exerohilum sp., Fusarium sp., and A. niger, the maximum degradation rate (98.34%) was achieved at the same concentration after 10 days. The mixed culture of Exerohilum sp. and Fusarium sp. demonstrated the highest degradation rates of (92.14% and 55.74%) at 8 and 12 ppm concentrations, respectively, after 10 days of incubation. Aspergillus niger (وكانت 69.66 و % 99.96 التتابع على)% بعد 10 و 20 الفطريات من المكونة الفطرية المزرعة اما الحضن. من يوم A. niger Exerohilum sp. و Fusarium sp., تكسير نسبة اعلى سجلت فقد وبلغت حيوي (98.34%) بعد 10 سجلت السابق. التركيز ولنفس الحضن من ايام للفطرين المختلطة المزرعة Exerohilum sp. و Fusarium sp. بلغ حيوي تكسير نسبة اعلى سجلت فقد 92.14) و % 55.74 بتركيز)% 8 و 12 بالمليون جزء الحضن. من ايام عشرة بعد الي التو على المفتاحية الكلمات : مختلطة. الت عز الحيوي، التربة،التكسير فطريات ايم، كاربندز
The study of three roadsoil contamination in the Sfax region by polycyclic aromatic hydrocarbons showed a significant variation between the three sites and proportional to the distance from the road. The variation between the physicochemical characteristics of three soils influenced the spatial distribution of polycyclic aromatic hydroacarbons. Quantitatively, the soils near Manzel Chaker road had the highest content followed by those of the Tunis road soil . Qualitatively, chrysene, benzo (b) fluorenthene;benzo (a) anthracene and Indeno (1.2.3.cd) pyrene were the most abundant compounds. These contaminants, with naphthalene and fluorenthene, affected the germination and aerial growth of tomato but with no significant effect on the germination and growth of cucumber which has shown resistance to pollution by polycylic aromatic hydrocarbons. The use of PCA and regression between parameters indicated that these compounds which are in mixture in soil have disturbed the germinative capacity, the speed of germination and the aerial elongation of tomato. In the same soils, the cucumber showed resistance to this contamination and its germination was not affected.
Oil spill contamination occurs due to exploration activities in the deep sea and downstream activities such as oil transportation via pipelines, oil-tankers (marine and terrestrial), re-fineries, finished product storage, distribution, and retail distribution setup. Physico-chemical technologies are accessible for oil spill clean-up, but oil bioremediation technologies are proven to be more affordable and environmentally friendly. The aim of this book chapter is to give deeper knowledge about the bioremediation technology of oil spills. This chapter discusses the nature and
composition of crude oil, bioremediation agents and strategies, bioremediation on different matrices (water, soil sludge), application strategy, and future prospect of bioremediation technology.
Agrochemicals in the form of fertilizers and pesticides were thought of as a boon for humankind. However, the advancement of science brought to the fore the fact that chemical fertilizers and pesticides cause considerable harm to soil and subsequently to groundwater. With the burden of feeding a burgeoning global population, modern agriculture is heavily dependent on the extensive use of agrochemicals. Given the fact that the human population will likely reach ~9.7 billion by 2050, the importance of agrochemicals is more than ever before. However, these agrochemicals are inherently persistent in nature and may degrade soil health and the utility of groundwater for various purposes. Soil microbial communities that sustain different nutrient cycles are affected to a great extent by the persistence of these recalcitrant agrochemicals. As humans are dependent on soil and water for their survival, they are also exposed to health hazards stemming from these agrochemicals. Contaminated groundwater, if consumed for a considerable period, may cause many human health problems, including hormone disruption, reproductive abnormalities, and cancer, etc. This chapter aims at reviewing various impacts of chemical fertilizers and pesticides on soil degradation, groundwater, and human health with some reference to Bangladesh perspective and suggesting ameliorative measures that would keep soil and associated ecosystems sustainable and lessen the health hazards for humans.
This study was amid to isolate soil fungi from agriculture soil and study their roles in the biodegradation of carbendazim fungicide at different concentrations were explored for two periods of incubation. Results showed the highest degradation rates of carbendazim at 4 part per million (ppm) concentration were observed by using single culture of Aspergillus niger (69.66% and 99.96% after 10 and 20 days, respectively).In the mixed cultures of Exerohilum sp., Fusarium sp., and A. niger, the maximum degradation rate (98.34%) was achieved at the same concentration after 10 days. The mixed culture of Exerohilum sp. and Fusarium sp. demonstrated the highest degradation rates of (92.14% and 55.74%) at 8 and 12 ppm concentrations, respectively, after 10 days of incubation. Aspergillus niger (وكانت 69.66 و % 99.96 التتابع على)% بعد 10 و 20 الفطريات من المكونة الفطرية المزرعة اما الحضن. من يوم A. niger Exerohilum sp. و Fusarium sp., تكسير نسبة اعلى سجلت فقد وبلغت حيوي (98.34%) بعد 10 سجلت السابق. التركيز ولنفس الحضن من ايام للفطرين المختلطة المزرعة Exerohilum sp. و Fusarium sp. بلغ حيوي تكسير نسبة اعلى سجلت فقد 92.14) و % 55.74 بتركيز)% 8 و 12 بالمليون جزء الحضن. من ايام عشرة بعد الي التو على المفتاحية الكلمات : مختلطة. الت عز الحيوي، التربة،التكسير فطريات ايم، كاربندز
There is interest in the effect of environmental factors on the potential for bioremediation of xenobiotic compounds with extended half-lives, especially in terrestrial ecosytems. Bacteria, including actinomycetes, yeasts, and filamentous fungi have been used to enhance the degradation of xenobiotic compounds in different ecosystems. Filamentous fungi are particularly suited to colonization of terrestrial ecosystems because of their mycelial mode of growth and the capacity for the production of significant amounts of extracellular enzymes, especially laccases and ligninases. However, few studies have examined the effect of changes in water and temperature relations on the activity of biorememdial microbial inoculants on xenobiotic compounds, and even less on mixtures of such compounds including crude oil. This chapter examines the effect of environmental factors on the differential breakdown of mixtures of pesticides such as chlorpyrifos, linuron, metribuzin and simazine, trifluralin and dieldrin, and polyaromatic hydrocarbons by different microbial inoculants, especially basidiomycetes including Trametes, Peniophora, Irpex, Picnosporus, and Phanerochaete species. These studies have shown that water stress of −0.7 or −2.8 MPa water potential had a differential effect on the breakdown of components of mixtures of pesticides which was reflected in the actual kinetics of degradation. Water stress also impacted on the amounts of key extracellular enzymes produced by the candidate bioremedial inoculants. This also suggests that breakdown of pesticides occurs over a wider range than that allowing plant growth which is limited at −1.4 MPa water potential. The use of different carriers to incorporate the inoculant microorganisms into terrestrial ecosystems may also affect the relative rates of breakdown of the individual or mixture of xenobiotic compounds. The implications of these results will be discussed in this chapter.
The White Fungus, which causes white rot on tree trunks, belongs to the basidiomycetes. Research into the microbiology of White-rot fungi has focused on engineering processes related to factors such as cell growth and enzyme production processes, and to smaller, i.e., molecular biology. Many studies have been conducted to select issues with high or specific biodegradation performance in a variety of ways. Production inhibitors have been used to improve enzyme production. Investigators are investigating different carriers (Stainless Steel net, polyamide fiber net, fiberglass net and polyurethane foam) to impair P.chrysosporium ligninolytic enzyme production. In this review, Pathophysiology, Microbiology, impact factors, treatments and alternative uses show white mold formation in biotransformation. The white fungus is being investigated to produce biotechnology for the reduction of a broad spectrum, a natural pollutant based on lignin-deficient enzymes. This in particular covers the destruction of many wastes and environmental pollution, including wastewater, pesticides, toxic natural pollutants, chlorinated hydrocarbons, etc. It will be updated.
Microbial-induced degradation of aromatic organic compounds and mineralization of zinc ions have attracted much attention because of its low cost, simple operation and quick response. This research, toluene was decomposed and made the concentration of carbonate ions increased accordingly by the enzymatic pressing of microorganisms, meanwhile carbonate ions mineralized zinc ions into carbonate precipitations. The composition and microstructure were analyzed systematically. The analysis results indicated that carbonate precipitations, basic zinc carbonate, could be successfully prepared by microbial method. The particle size of basic zinc carbonate was nanometer, and its shape was near-spherical. Furthermore, the phase composition, functional groups and surface morphology of the precipitations prepared by different methods were basically the same. This work provided a new method for remediation of zinc ion pollution based on the degradation of toluene.
Human disturbance has become the primary driving factor behind declining urban wetland ecological health due to rapid urbanization. Sediment microbial communities are critical for wetland ecosystem functioning but experience a range of natural and anthropogenic stressors due to rapid urbanization and land use changes, especially in developing countries. Polycyclic aromatic hydrocarbons (PAHs) released into the environment primarily come from anthropogenic sources like industrial activities and traffic emissions. Environmental PAH contamination is accelerating due to rapid urbanization, which also increases potential PAH-related dangers to human health. However, PAHs are widely distributed and not easy to centrally control. Microorganisms are the primary mediators of wetland purification, with most PAH-degrading microorganisms being bacteria. To better understand the influence of PAH contamination on urban wetland microbial communities, bacterial community compositions within sediments of urban wetlands in three land use types were investigated using high-throughput DNA sequencing and bioinformatics analyses. Statistical analyses revealed significant differences in overall microbial compositions among the three land use types, although γ-proteobacteria was the dominant phyla across all samples. Among the potential PAH-degrading bacterial taxa in sediments, Sphingomonas was the most prevalent. The distributions of PAH-degrading taxa were primarily affected by variance in organic compound abundances in addition to various physico-chemical variables, among which high-ring PAH content was a key parameter associated with bacterial distributions, except in the riverine wetlands. Functional inference via phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) indicated that 30 of the 43 genes related to PAH metabolism were predicted to be present within the genomes of bacteria among the three land use type. In particular, dioxygenase and dehydrogenase genes involved in PAH degradation were inferred to be prevalent, indicating that the host urban wetlands exhibited strong potential for organic pollutant degradation.
Waste asphalt shingle (WAS) has traditionally been disposed of by landfilling due to environmental concerns surrounding Polycyclic aromatic hydrocarbons in WAS, which may potentially leach out, causing environmental pollution. However, this disposal method has been less environmentally acceptable and less cost effective than in the past due to concern on land resources. This study evaluates the potential of degradation of WAS, therefore reducing the polycyclic aromatic hydrocarbons (PAHs) content, by exploiting microbial biodegradation. The white rot fungus Phanerochaete chrysosporium was tested for its potential to degrade waste asphalt shingle binder. The biodegradation process was analyzed and quantified by both Fourier-transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). Results illustrate that P. chrysosporium can degrade WAS binder. GPC analysis indicates that the small asphaltic molecules were biodegraded preferentially by P. chrysosporium. The PAHs content of the WAS binder increased initially during fungal biodegradation, but subsequently decreased with the progression in biodegradation to a level lower than that of the original shingle binder. Results from this study could be used to develop solutions to the sustainable management of waste asphalt shingles.
To maximize better yield of the crops by any means in the recent agricultural practices, cultivators are applying today different kind of organic and inorganic chemical compounds in the form of fertilizers and pesticides with high rates of application. These chemical compounds often get deposited into soils and increase their concentrations beyond a certain threshold. Whenever the concentration of some chemical compounds increases beyond a threshold level then corresponding compounds may start interfering with the ecological processes, such soils are referred as ‘contaminated soil’. However, agricultural soil contamination not only interferes with the physiology and metabolism of crop plants, but also results in various health disorders to human beings. Among several contaminants of the soils, polycyclic aromatic hydrocarbons are highly hazardous and ubiquitously present in environment. Thus, soil contamination by polycyclic aromatic hydrocarbons needs to be carefully monitored and managed to minimize the impacts on global ecosystems and human health.
This study was amid to isolate soil fungi from agriculture soil and study their roles in the biodegradation of carbendazim fungicide at different concentrations were explored for two periods of incubation. Results showed the highest degradation rates of carbendazim at 4 part per million (ppm) concentration were observed by using single culture of Aspergillus niger (69.66% and 99.96% after 10 and 20 days, respectively).In the mixed cultures of Exerohilum sp., Fusarium sp., and A. niger, the maximum degradation rate (98.34%) was achieved at the same concentration after 10 days. The mixed culture of Exerohilum sp. and Fusarium sp. demonstrated the highest degradation rates of (92.14% and 55.74%) at 8 and 12 ppm concentrations, respectively, after 10 days of incubation. Aspergillus niger (وكانت 69.66 و % 99.96 التتابع على)% بعد 10 و 20 الفطريات من المكونة الفطرية المزرعة اما الحضن. من يوم A. niger Exerohilum sp. و Fusarium sp., تكسير نسبة اعلى سجلت فقد وبلغت حيوي (98.34%) بعد 10 سجلت السابق. التركيز ولنفس الحضن من ايام للفطرين المختلطة المزرعة Exerohilum sp. و Fusarium sp. بلغ حيوي تكسير نسبة اعلى سجلت فقد 92.14) و % 55.74 بتركيز)% 8 و 12 بالمليون جزء الحضن. من ايام عشرة بعد الي التو على المفتاحية الكلمات : مختلطة. الت عز الحيوي، التربة،التكسير فطريات ايم، كاربندز
In this study, derivatives of two common fatty acids in plant root exudates, sodium palmitate and sodium linoleate (sodium aliphatates), were added to an aged Polycyclic aromatic hydrocarbons (PAHs) contaminated soil to estimate their effectiveness in the removal of PAHs. Sodium linoleate was more effective in lowering PAHs and especially high-molecular-weight (4-6 ring) PAHs (HMW-PAHs). Principal coordinates analysis (PCoA) indicates that both amendments led to a shift in the soil bacterial community. Moreover, linear discriminant effect size (LEfSe) analysis demonstrates that the specific PAHs degraders Pseudomonas, Arenimonas, Pseudoxanthomonas and Lysobacter belonging to the γ-proteobacteria and Nocardia and Rhodococcus belonging to the Actinobacteria were the biomarkers of, respectively, sodium linoleate and sodium palmitate amendments. Correlation analysis suggests that four biomarkers in the sodium linoleate amendment treatment from γ-proteobacteria were all highly linearly negatively related to HMW-PAHs residues (p < 0.01) while two biomarkers in the sodium palmitate amendment treatment from Actinobacteria were highly linearly negatively related to LMW-PAHs residues (p < 0.01). Higher removal efficiency of PAHs (especially HMW-PAHs) in the sodium linoleate amendment treatment than in the sodium palmitate amendment treatment might be ascribed to the specific enrichment of microbes from the γ-proteobacteria. The bacterial functional KEGG orthologs (KOs) assigned to PAHs metabolism and functional C23O and C12O genes related to cleavage of the benzene ring were both up-regulated. These results provide new insight into the mechanisms of the two sodium aliphatate amendments in accelerating PAHs biodegradation and have implications for practical application in the remediation of PAHs-contaminated soils.
Environmental hazard is growing more and more due to the indiscriminate and frequently deliberate release of harmful substances. Use of chemicals in industrial processes including nuclear experiments, agricultural practices, and various aspects of our daily lives resulted into the release of potential hazardous chemicals into the environment either on purpose or by accident. These hazardous chemicals known to pollute the environment are pesticides, heavy metals, hydrocarbons, drugs, halogenated solvents, and agricultural chemicals. After their release into environment, these chemicals are transported through the water, soil, and atmosphere sources. Fungi play a very crucial role in bioremediation of hazardous chemicals owing to their robust morphology and diverse metabolic capacity. Fungal enzymes have potential to effectively transform and detoxify hazardous substances. They have been recognized to be able to transform pollutants at a detectable rate and are potentially suitable to restore polluted environments. The fungal degradation of xenobiotics is looked upon as an effective method of removing these pollutants from the environment by a process which is currently known as bioremediation. The present chapter focuses on different fungal groups secreted a number of enzymes from a variety of habitats with their role in bioremediation of different toxic and recalcitrant compounds. This chapter presents an extensive review of the fungal activities on hazardous chemicals, fungal diversity, and the use of fungi in the degradation of chemical pollutants, enzyme degrading systems, and perspectives on the use of fungi in bioremediation and unexplored research.
Fungi are capable of the degradation, utilisation and/or transformation of a wide variety of organic and inorganic substances, including xenobiotics, metals, radionuclides, and minerals. Fungal populations are therefore intimately involved in element cycling at local and global scales, and such processes have major implications for living organisms, notably plant productivity and human health. It also follows that impairment of fungal activity could have serious consequences for ecosystem function in view of their importance in terrestrial habitats and as plant symbionts. Their activities are part of natural biogeochemical cycles for major elements such as C, N, O, P and S but also metals and radionuclides, as well as having application in the natural attenuation or bioremediation of polluted sites. Despite the toxicity of organic and inorganic pollutants, fungi are ubiquitous inhabitants of polluted locations and exhibit a variety of mechanisms underpinning tolerance and survival. Some fungal transformations of pollutants have applications in environmental biotechnology, e.g. metal bioleaching, biorecovery and detoxification and xenobiotic and organic pollutant degradation and bioremediation. This chapter outlines some important interactions of fungi with organic and inorganic pollutants and highlights the interdisciplinary approach that is necessary to further understand the important roles that fungi play in pollutant transformations, the chemical and biological mechanisms that are involved, and their environmental and applied significance.
En México a pesar de poseer una elevada diversidad biológica, aún son pocos los
estudios encaminados a valorar su potencial biotecnológico. La prospección de la riqueza fúngica nativa en la búsqueda de enzimas de importancia biotecnológica es una actividad prioritaria ante la constante pérdida de la biodiversidad de los ecosistemas locales. Asimismo, la búsqueda de enzimas ligninolíticas con aplicación en biotecnología ambiental, podría ser la plataforma para ofrecer soluciones a problemas como la contaminación del suelo y agua por herbicidas, en donde la contaminación por atrazina representa el problema principal en numerosas zonas agrícolas del país. Ante este escenario, el objetivo central de este trabajo fue evaluar el uso de co-cultivos fúngicos de especies nativas en la producción de enzimas con potencial para la biorremediación de un suelo contaminado con atrazina. El objetivo central se abordó en cuatro etapas experimentales sucesivas. En la primera se colectaron y aislaron hongos macroscópicos ligninolíticos (HML) de diversos ecosistemas del estado de Veracruz. En total se aislaron 47 cepas nativas; mediante pruebas cualitativas para la detección de actividad lacasa y manganeso peroxidasa (MnP), se efectuó una selección de las cepas para los ensayos subsecuentes. Los aislamientos se identificaron taxonómicamente mediante las características macro y microscópicas de sus basidiocarpos, solo se identificó a nivel
molecular la especie Trametes maxima, debido a su importancia en el desarrollo de la mayoría de los experimentos. Los hongos microscópicos de suelo (HMS) empleados para el desarrollo de los co-cultivos, se obtuvieron del Laboratorio de Micromicetos del Instituto de Ecología A. C. De todas las especies reactivadas y empleadas en este estudio, únicamente se corroboró la identidad de Paecilomyces carneus a través de biología molecular. En la segunda etapa se evaluó la tolerancia a la atrazina en HML y HMS a través de bioensayos dosis respuesta. Además, en los HML se cuantificó la actividad lacasa y MnP bajo condiciones de estrés por las concentraciones de atrazina. De acuerdo a la concentración efectiva media (CE50) calculada, Pleurotus sp. cepa 1 (CE50 = 2281.0 mg L-1) fue significativamente más tolerante a la atrazina en comparación con las otras cepas estudiadas, a pesar de que su actividad enzimática (lacasa = 1.4 U mg proteína-1 y MnP = no se detectó) fue significativamente menor (p< 0.05) al resto de los aislamientos evaluados. Para los subsecuentes experimentos en co-cultivos fueron seleccionadas las cepas con mediana tolerancia a la atrazina y alta actividad lacasa como Daedalea elegans (CE50 = 1088.0 mg L-1 y 29.3 U mg proteína-1), Pycnoporus sanguineus (CE50
= 1311.0 mg L-1 y 62.4 U mg proteína-1) y Trametes maxima (CE50 = 1532.0 mg L-1 y 120.6 U mg proteína-1). En cuanto a los HMS, las especies más tolerantes a la atrazina fueron Paecilomyces carneus, P. lilacinus y P. marquandii al presentar alta CE50 con 6820.0, 3633.0 y 4736.0 mg L-1 de atrazina, respectivamente. En la tercera etapa se estudiaron las interacciones fúngicas en 9 co-cultivos establecidos entre HML (Daedalea elegans, Pycnoporus sanguineus y Trametes maxima) y HMS (Paecilomyces carneus, P. lilacinus y Aspergillus tamarii) como estrategia para incrementar las actividades enzimáticas en los HML (lacasa y MnP). Los co-cultivos se desarrollaron en medio
de cultivo líquido Sivakumar modificado. Además, se evaluó el efecto del tiempo de inoculación de los HMS sobre los HML en la producción de lacasa y MnP. Posteriormente, para contribuir con la generación de conocimiento en el área de co-cultivos fúngicos, se seleccionó el co-cultivo T. maxima–P. carneus para evaluar los factores nutrimentales que influyen en la actividad enzimática del sistema, a través de un Diseño Experimental Plackett-Burman (DEPB) con 11 factores independientes, dos niveles cada uno y cuatro puntos centrales.
La inoculación del HMS sobre los HML a los 3 y 5 días después del establecimiento de
los HML en el medio de cultivo, mostró un incremento significativo en la producción de lacasa y MnP, cuando se comparó con el monocultivo (HML) y co-cultivo inoculado simultáneamente. Con 5 días de desfasamiento en su inoculación, Paecilomyces lilacinus incrementó la actividad lacasa de D. elegans, P. sanguineus y T. maxima en 0.3, 0.9 y 1.1 veces más, respecto a los monocultivos de cada hongo. Asimismo, Paecilomyces carneus incrementó la actividad lacasa en D. elegans y T. maxima en 0.5 y 0.78 veces más, respectivamente. En cuanto a la MnP, P. carneus y P. lilacinus incrementaron la actividad MnP en P. sanguineus y T. maxima en un intervalo de 0.3 a 3.6 veces más.
Los resultados del DEPB en el co-cultivo T. maxima - P. carneus indicaron que la
modificación del medio de cultivo incrementó la actividad lacasa y MnP en 1.8 y 2.8 veces más. Además de la cantidad de inóculo (2 discos de micelio-agar), los elementos que favorecieron significativamente (p < 0.05) a la actividad lacasa fueron: altas concentraciones de glucosa (30 g L-1), (NH4)2SO4 (0.075 g L-1) y MnSO4 (0.0015 g L-1), y bajas concentraciones de KH2PO4 (0.5 g L-1) y FeSO4 (0.005 g L-1). Mientras que la actividad MnP fue favorecida por altas concentraciones de extracto de levadura (3.75 g L-1), MgSO4 (0.75 g L-1), CaCl2 (0.015 g L-1) y MnSO4 (0.0015 g L-1).
La cuarta y última etapa consistió en evaluar, a nivel de microcosmos, la degradación de
atrazina en un suelo migajón-arcilloso mediante la adición de extractos enzimáticos de
monocultivos de T. maxima, P. carneus y A. tamarii, y de los co-cultivos T. maxima–P. carneus y T. maxima–A. tamarii. Además, se aplicó un diseño experimental factorial 24 para evaluar la influencia del tipo de extracto, esterilización del suelo, capacidad de campo y pH del suelo en la degradación de atrazina. Los principales resultados indicaron que el extracto de monocultivo de T. maxima y su co-cultivo con P. carneus degradaron la atrazina (5 μg g-1) al 100%. Sin embargo, se encontraron diferencias significativas (p < 0.05) en el tiempo medio de degradación (TD50), el cual fue más bajo para el monocultivo de T. maxima (0.3 h) respecto a su co-cultivo con P. carneus (1.2 h). El diseño factorial 24 indicó que la degradación de atrazina en los microcosmos fue influenciado significativamente por el tipo de extracto (p = 0.03) y el pH del suelo (p = 0.01), el extracto de monocultivo de T. maxima adicionado a un suelo con pH ácido (4.86) favoreció la degradación de la atrazina. Los resultados obtenidos permiten concluir que los sistemas de co-cultivos podrían ser empleados para potencializar la producción de enzimas, y en
la degradación de la atrazina en suelo. Asimismo, los diferentes aspectos involucrados en este estudio, muestran la complejidad de la investigación en micorremediación, el cual debe ser abordado de manera multidisciplinaria.
Coal tar is a complex mixture of a large number of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic compounds. The terahertz (THz) spectral properties of coal tar are studied by terahertz time-domain spectroscopy (THz-TDS). The absorption coefficient, refractive index, and relative permittivity of coal tar in the range of 0.2–2.5 THz are determined. Compared with pure cyclic hydrocarbons such as benzene, quinolone, and carbazole that are able to be extracted from coal tar, it is surprising to find that coal tar has a higher transmittance to THz waves than its pure components.
Eight rapid Poly R-478 dye-decolorizing isolates from The Netherlands were screened in this study for the biodegradation of polycyclic aromatic hydrocarbons (PAH) supplied at 10 mg liter(-1). Several well-known ligninolytic culture collection strains, Phanerochaete chrysosporium BKM-F-1767, Trametes versicolor Paprican 52, and Bjerkandera adusta CBS 595.78 were tested in parallel. All of the strains significantly removed anthracene, and nine of the strains significantly removed benzo(a)pyrene beyond the limited losses observed in sterile liquid and HgCl2-poisoned fungus controls. One of the new isolates, Bjerkandera sp. strain Bos 55, was the best degrader of both anthracene and benzo(a)pyrene, removing 99.2 and 83.1% of these compounds after 28 days, respectively. Half of the strains, exemplified by strains of the genera Bjerkandera and Phanerochaete, converted anthracene to anthraquinone, which was found to be a dead-end metabolite, in high yields. The extracellular fluids of selected strains were shown to be implicated in this conversion. In contrast, four Trametes strains removed anthracene without significant accumulation of the quinone. The ability of Trametes strains to degrade anthraquinone was confirmed in this study. None of the strains accumulated PAH quinones during benzo(a)pyrene degradation. Biodegradation of PAH by the various strains was highly correlated to the rate by which they decolorized Poly R-478 dye, demonstrating that ligninolytic indicators are useful in screening for promising PAH-degrading white rot fungal strains.
This paper presents a brief overview of research on polycyclic aromatic hydrocarbon biodegradation by white-rot fungi during the 1990s. The fungi studied, the biological aspects of the methodology employed and the main results obtained are summarised and discussed. This provides a timely and improved understanding of recent findings and issues in white-rot fungi research, and highlights new areas of research that are under way. Despite the large amount of published work, it remains difficult to make gen-eral conclusions or recommendations from the results because of the different condi-tions used in the experiments.
The degradation rate of benzo(a)pyrene (B(a)P), a 5-ring PAH compound, was significantly enhanced in fungal (Phanerochaete chrysosporium) enriched soil composting microcosm reactors over that observed in unamended soil systems. The maximum B(a)P removal rate was 1.1 μg/g-soil-day with fungal inoculation compared to 0.24 μg/g-soil-day without fungal inoculation for a silt loam Kidman soil. Mass balance considerations suggested that the enhanced removal of B(a)P resulted in the formation of bound contaminant carbon residues in soil. A maximum bound residue formation rate of 0.37 μg/g-soil-day was estimated in fungal inoculated microcosms. This was significantly different from the zero rate under natural soil conditions. The observed B(a) mineralization rates were less affected by fungal activity than was B(a)P removal. Degradation of B(a)P resulted in humification (i.e. polymerization) of most of contaminant carbon rather than conversion to COâ. The fraction of contaminant carbon that was humified compared to that which was mineralized was dependent on soil type. A multi-compartment structural activity model has been developed to illustrate the overall degradation of B(a)P during soil composting.
This review has considered the feasibility of applying current microbial treatment techniques to the remediation of former gasworks. Success would appear dependent upon the contaminants of interest being biodegradable and an effective means of implementation. Contaminants of concern at gasworks include PAH, phenols and cyanides. Laboratory and field studies suggest that these contaminants are biodegradable although little data exists with respect to mixtures in the form present at gasworks. Further research is recommended in this respect. Subsurface investigations of gasworks have revealed an extremely heterogeneous environment which suggests that current in situ remedial techniques may be unsuitable. Techniques that excavate and homogenise the contamination prior to treatment may improve the chances of successful remediation. Pilot studies appear successful but future research should emphasise a mass balance approach where the significance of non biological degradative mechanisms can be assessed. Contaminated groundwaters appear amenable to treatment in surface reactors. The success of overall remediation will however be dependent on the efficiency of the hydraulic withdrawal system used. The implementation of such a scheme should only be undertaken with a clear understanding of the limitations of this technology.
Inoculation of the benzo(a)pyrene (B(aP) contaminated soil composting system with the white rot fungus Phanerochaete chrysosporium increased the rate of bound residue formation of contaminant carbon from 0.73 mg B(a)P/kg-day to 1.58 mg B(a)P/kg-day over the first 30 days of investigation. Despite this initial enhancement in contaminant removal, fungal inoculation was found to be ineffective in significantly enhancing the extent of benzo(a)pyrene during the 95 day composting study. The extent of contaminant removal was 62.8 ± 5.9%, 65.6 ± 1.2% and 49.3 ± 0.5% for the fungal inoculated, fungal uninoculated and poisoned compost reactors, respectively. First order modeling of removal kinetics yielded contaminant half lives of 11.5, 8.6 and 230 days for the fungal inoculated, uninoculated and poisoned compost reactor systems, respectively. Analysis of soil systems revealed appreciable numbers of PAH degrading fungi ( > 1 × 104 CFU/gm) in the uninoculated compost systems at the end of the 95 day treatment period.Analysis of volatile traps indicated that neither mineralization nor vapor partitioning of benzo(a)pyrene (or its chemical intermediates) was significant during the soil composting process. Bound residue formation was found to be the predominant transformation mechanism for benzo(a)pyrene in the microbially active compost systems accounting for nearly 100% of the benzo(a)pyrene removed.
Various 14C-radiolabeled and unlabeled substrates have been used to screen for ligninolytic activity. However, these assays are relatively slow and cumbersome and often require synthesis of substrates that are not commercially available. The polymeric dyes used in these assays are inexpensive and can be obtained commercially in high purity. They are stable and readily soluble, have high extinction coefficients, and low toxicity toward Phanerochaete chrysosporium and other white rot fungi and bacteria tested, o-Anisidin and other low-molecular-weight dyes that have been used in similar assays could be taken into the cells, whereas polymeric dyes will remain extracellular, at least during the initial stages of degradation, and thus will provide a better model for lignin degradation. A growing body of evidence indicates that the dyes serve as substrates for at least some component(s) of the lignin degradative system and that dye decolorization is correlated with the onset of secondary metabolism and ligninolytic activity. Recent studies indicate that only lignin-degrading fungi are able to decolorize the dye Poly B-411 and that efficiency of decolorization is correlated with the ability to degrade several lignin model compounds.
Based on the known ability of the white rot fungus Phanerochaete chrysosporium to metabolize PAHs, a fungal reactor system with separate soil extraction and fungal incubation units was constructed. The design of the system allowed samples to be easily removed at strategic positions and to ascertain mineralization. The highly contaminated soil (1−2 mm particle diameter), with a total EPA Method 610 concentration of 41 g of PAHs kg-1, was spiked with [7,10-14C]benzo[a]pyrene in order to follow the fate of this tracer by HPLC and high-performance gel permeation chro matography. While mineralization amounted to only 2.5%, it was observed that the fungus reduced the total soil PAH concentration by 45% through polymerization processes. For [7,10-14C]benzo[a]pyrene, a value of 4.9 mg kg-1 day-1 or overall 5.5% was obtained. The polymers remained as sociated with soil, and no monomeric PAHs were detected in the medium. In parallel experiments without soil, high molecular weight polymers could be found in the medium. Sterile soil and medium controls revealed no polymerization. The results were consistent with literature reports that P. chrysosporium converts PAHs primarily to quinones, which have a strong tendency to polymerize. On the basis of the success of this system, scaling up appears to be justifiable.
A field study to determine the ability of selected lignin-degrading fungi to remediate soil contaminated with creosote was performed at a wood-treating facility in south central Mississippi in the autumn of 1991. The effects of solid-phase bioremediation with Phanerochaete sordida and of two control treatments on soil concentrations of 14 priority pollutant polycyclic aromatic hydrocarbon (PAH) components of creosote were followed for 56 days. PAH analytes containing ≥5 rings persisted at their original concentrations in all treatments. However, depletion of 3-ring (85-95%) and 4-ring (24-72%) analytes after 56 days was greater in the fungal treatment than in control treatments in all cases. This finding demonstrates the potential of lignin-degrading fungi in the solid-phase bioremediation of creosote-contaminated soils. However, the persistence of the larger analytes represents a significant challenge to this developing technology.
Studies on a variety of chemical carcinogens have demonstrated that their ultimate reactive and carcinogenic forms are strong electrophiles. Some carcinogens, such as alkylating agents, are in their ultimate forms as administered, but most require metabolism to these active derivatives. The ultimate carcinogens react, usually non-enzymatically, with nucleophilic constituents in vivo. Of particular interest in regard to their possible importance in carcinogenesis have been the covalent interactions of these electrophilic reactants with cellular informational macromolecules, the DNAs, RNAs, and proteins. Current data are consistent with the idea that the initiation step of chemical carcinogenesis is a mutagenic event and is caused by alteration of DNA by the ultimate carcinogens. The nature of the carcinogen metabolite(s) involved in the promotion phase has not been determined, but there appears to be no requirement that they be electrophilic. The development of the concept of ultimate chemical carcinogens as strong electrophilic reactants is reviewed, especially with respect to the studies carried out in the authors' laboratory.
The timing of onset of mineralization of pyrene by Phanerochaete chrysosporium correlated with the production of ligninase activity as monitored by the decolorization of the polymeric dye Poly R-478. A layer of native soil decreased the growth of P. chrysosporium by visual assessment of hyphal mass and measurement of ergosterol, a fungal membrane sterol. The native soil layer slowed the production of ligninase as determined by Poly R-478 decolorization and the rate of mineralization of pyrene was decreased. Inhibition of pyrene mineralization was also observed with layers of sterilized silt and clay but not by sand. Mineralization, fungal growth and rate of decolorization of the dye were improved when the native soil was sterilized by autoclaving. Suspensions of the native soil contained a consortium of bacteria and fungi. Several of the bacteria were antagonistic to the growth of P. chrysosporium on solid medium. The onset of dye decolorization by P. chrysosporium on a nitrogen-limited medium was delayed by certain bacteria. These findings suggest that in certain soils, bioremediation by P. chrysosporium could be suppressed by indigenous soil microbes as well as by the abiotic features of the soil composition.
The colonization of sandy loam soil following inoculation with spore suspensions of the white-rot fungi Phanerochaete chrysosporium ATCC 24725 and Chrysosporium lignorum CL1 was confirmed by an epifluorescence microscopy-image analysis method. These fungi and Trametes versicolor PV1 mineralized 3,4-dichloroaniline and benzo(a)pyrene in soil at concentrations up to 250 μg g−1. Successful inoculation and biodegradation required supplementary carbon sources. Addition of inorganic nutrients had no stimulatory effect. Glucose, hay, wood chips, pine bark, loam and peat all promoted growth and degradation but chopped wheat straw was the best substrate.Increasing the content of straw in the soil led to increased biomass and mineralization. The optimum ratio of straw: soil for mineralization was 1:4. Both strains sporulated within 7 days of inoculation before a further increase in hyphal growth but this had no effect on the mineralization rate. These results indicate that use of white-rot fungi in biotechnological soil treatment may be feasible.
The ability of the white rot fungus Phanerochaete chrysosporium to enhance the biotransformation of benzo(a)pyrene (B(a)P) in contaminated soils was evaluated in compost bioreactors. Radiolabelled114C and chemical mass balances were used to evaluate: 1) rate of disappearance of test compound; 2) mineralization; 3) formation of bound contaminant residue; and 4) treatment costs.
Mineralization of B(a)P was found to be insignificant over the duration of test period. Moreover, no radioactivity was recovered in volatile organic traps indicating that transformation of B(a)P resulted in chemicals intermediates that remained associated with the compost matrix.
Bound contaminant residue formation was found to be the major mechanism of B(a)P removal accounting for nearly 100% of the contaminant loss from the solvent extract (methylene chloride/acetone). A maximum rate of bound contaminant removal of 1.36 mg B(a)P/Kg soil-day was estimated in fungal inoculated system over the first thirty days of treatment. This was significantly different from the maximum rate of bound residue formation estimated in the noninoculated systems (0.83 mg B(a)P/Kg soil-day) over the same time period. After thirty days, the rate of bound residue formation decreased to near zero in the inoculated system while remaining constant in the noninoculated reactors. The decrease in bound residue formation coincided with decline in benzo(a)pyrene removal. Data suggest that fungal activity may have been reduced over time by nutrient limitation.
In recent years, the white rot fungus Phanerochaete chrysosporium has shown promise as an organism suitable for the breakdown of a broad spectrum of environmental pollutants, including polynuclear aromatic hydrocarbons (PAHs). The focus of this study was to determine whether P. chrysosporium could effectively operate in an actual field sample of oil tar-contaminated soil. The soil was loaded with [14C]phenanthrene to serve as a model compound representative of the PAHs. Soil with the native flora present under static, aerobic conditions with buffering (pH 5.0 to 5.5) displayed full mineralization on the order of 20% in 21 days. The addition of P. chrysosporium was synergistic, with full mineralization on the order of 38% in 21 days. In addition to full mineralization, there was an increase in the proportion of radiolabelled polar extractives, both soluble and bound, in the presence of P. chrysosporium. From this study, it is apparent that the native soil microflora can be prompted into full mineralization of PAHs in some contaminated soils and that this mineralization can be enhanced when supplemented with the white rot fungus P. chrysosporium. With further refinement, this system may prove an effective bioremediation technology for soils contaminated with PAHs.
The effect of soil microorganisms on mineralization of 14C-labelled pyrene by white-rot fungi in solid-state fermentation was investigated. Two strains of white-rot fungi, Dichomitus squalens and a Pleurotus sp., were tested. The fungi were incubated on milled wheat straw contaminated with [14C]pyrene for 15 weeks. CO2 and 14CO2 liberated from the cultures were determined weekly. To study the effect of soil microorganisms on respiration and [14C]pyrene mineralization in different periods of fungal development, the fungal substrate was covered with soil at different times of incubation (after 0, 1, 3, 5, 7, 9 or 11 weeks). The two fungi showed contrasting ecological behaviour in competition with the soil microflora. Pleurotus sp. was highly resistant to microbial attack and had the ability to penetrate the soil. D. squalens was less competitive and did not colonize the soil. The resistance of the fungus was dependent on the duration of fungal preincubation. Mineralization of [14C]pyrene by mixed cultures of D. squalens and soil microorganisms was higher than by the fungus or the soil microflora alone when soil was added after 3 weeks of incubation or later. With Pleurotus sp., the mineralization of [14C]pyrene was enhanced by the soil microflora irrespective of the time of soil application. With D. squalens, which in pure culture mineralized less [14C]pyrene than did Pleurotus sp., the increase of [14C]pyrene mineralization caused by soil application was higher than with Pleurotus sp.
The microbial remediation of former gasworks sites: a review Suppres-sion of bioremediation by Phanerochaete chrysosporium by soil factors
- A O Thomas
- J N Lester
- ±
- B Tucker
- C Radtke
- S.-I Kwon
- A J Anderson
Thomas, A.O., Lester, J.N., 1993. The microbial remediation of former gasworks sites: a review. Environ. Technol. 14, 1±24. Tucker, B., Radtke, C., Kwon, S.-I., Anderson, A.J., 1995. Suppres-sion of bioremediation by Phanerochaete chrysosporium by soil factors. J. Hazardous Mat. 41, 251±265. R. Canet et al. / Bioresource Technology 76 (2001) 113±117
Remediation of petroleum impacted soils in fungal compost bioreactors Searches for ultimate chemical carcinogens and their reactions with cellular macromolecules
- M J Mcfarland
- X J Qiu
- J L Sims
- M E Randolph
- R C Sims
McFarland, M.J., Qiu, X.J., Sims, J.L., Randolph, M.E., Sims, R.C, 1992. Remediation of petroleum impacted soils in fungal compost bioreactors. Water Sci. Technol. 25, 197±206. Miller, E.C., Miller, J.A, 1981. Searches for ultimate chemical carcinogens and their reactions with cellular macromolecules. Cancer 47, 2327±2345.
An investigation into the bioremediation of polycyclic aromatic hydrocarbons in a manufactured gas plant soil
- J G.A Birnstingl