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At least 19 recordsLinked to original sources
PubMed2004

Immobilized white-rot fungal biodegradation of phenol and chlorinated phenol in trickling packed-bed reactors by employing sequencing batch operation.

The biodegradation of phenol and 2,4,6-trichlorophenol (2,4,6-TCP) by immobilized white-rot fungal cultures was studied in pinewood chip and foam glass bead-packed trickling reactors. The reactors were operated in sequencing batch format. Removal efficiency increased over time and elevated influent phenol and 2,4,6-TCP (800 and 85 mg l(-1)) concentrations were removed by greater than 98% in 24-30 h batch cycles. Comparable performance between the packing materials was shown. Increased lignin peroxidase (LiP) activity was detected with the introduction of the compounds and optimum activity corresponded to optimum removal periods. Higher LiP activity (16.7-19 Ul(-1)) was detected in glass bead-packed reactor compared to wood chip reactor (0.2-5 Ul(-1)). The presence of Mn(2+) in the wood material possibly effected elevated manganese peroxidase (MnP) activity (0.3-5.8 Ul(-1)) compared to low to negligible activity in the glass bead reactor. Reactor performances are discussed in relation to sequencing batch operation and nutrient requirements necessary to induce and sustain fungal enzyme activity in inert vs. organic material packed systems.

Basidiomycota↗
PubMed2005

Fungal biodegradation of naphthalene: microcosms studies.

The present work is aimed to ascertain naphthalene biodegradation capability of P. chrysosporium and T. harzianum in soil microcosms. Considering the high naphthalene volatility, a suitable soil microcosm was set-up and used. Several degradation tests were conducted with different C/N ratio media for the two fungi in order to enquire the best range of working conditions. The kinetic studies were conducted at a maximal naphthalene concentration of 600 mg kg(-1). During experimental time course naphthalene concentration, CO2 evolution as well as phytotoxicity tests were performed as monitoring parameters. The results shown in the current paper, put in evidence that T. harzianum, differently than in liquid culture, is not able to biodegrade naphthalene directly in soil microcosm, while P. chrysosporium in the same conditions biodegrades the PAH till about 600 mg kg(-1). As concern the founded kinetics for P. chrysosporium, a saturation shape in presence of N-limited medium (high C/N ratio) was evaluated while a growing form more than linear in no-N limited medium (normal C/N ratio) was determined.

Basidiomycota↗
PubMed1983

Fungal biodegradation and biotransformation of soluble lignocarbohydrate complexes from straw.

Aspergillus japonicus is an efficient degrader of phenolics and carbohydrates present in a mixture of soluble lignocarbohydrate complexes extracted from wheat straw. Trichoderma sp. attacked part of the carbohydrate but hardly affected the aromatic portion of this solution. Polyporus versicolor had a complex effect; polymerization of low-molecular-size phenolics accompanied the degradation of aromatic and carbohydrate polymers. The addition of xylose to the medium facilitated depolymerization of lignin by the fungi tested and prevented the polymerization of low-molecular-size fractions of lignocarbohydrate complexes by P. versicolor. P. versicolor, in contrast to A. japonicus and Trichoderma sp., also excreted into the medium considerable amounts of laccase, but only in the absence of endogenous or exogenous carbohydrates. Apparently, laccase is involved in polymerization rather than degradation of lignin in this organism. A number of extracellular glycanases were also secreted by these fungi.

Journal Article↗
PubMed1992

Fungal biodegradation of lignopolystyrene graft copolymers.

White rot basidiomycetes were able to biodegrade styrene (1-phenylethene) graft copolymers of lignin containing different proportions of lignin and polystyrene [poly(1-phenylethylene)]. The biodegradation tests were run on lignin-styrene copolymerization products which contained 10.3, 32.2, and 50.4% (wt/wt) lignin. The polymer samples were incubated with the white rot fungi Pleurotus ostreatus, Phanerochaete chrysosporium, and Trametes versicolor and the brown rot fungus Gloeophyllum trabeum. White rot fungi degraded the plastic samples at a rate which increased with increasing lignin content in the copolymer sample. Both polystyrene and lignin components of the copolymer were readily degraded. Polystyrene pellets were not degradable in these tests. Degradation was verified for both incubated and control samples by weight loss, quantitative UV spectrophotometric analysis of both lignin and styrene residues, scanning electron microscopy of the plastic surface, and the presence of enzymes active in degradation during incubation. Brown rot fungus did not affect any of the plastics. White rot fungi produced and secreted oxidative enzymes associated with lignin degradation in liquid media during incubation with lignin-polystyrene copolymer.

Basidiomycota↗
PubMed2006

Chemical and biological properties of wheat soil in response to paddy straw incorporation and its biodegradation by fungal inoculants.

A field experiment was conducted to evaluate the relative contribution of organic fertilizers (paddy straw, microbial inoculants and vermicompost) and inorganic fertilizers (urea and superphosphate) in improving pH, C, N, humus, microbial biomass, dehydrogenase, phosphatase, cellulase, beta-glucosidase and xylanase activities of soil under wheat crop. Vermicompost fertilization resulted in highest microbial biomass, available phosphorus, and nitrogen content of wheat soil. It was also found effective in minimizing the alkalinity of soil compared to other treatments as indicated by pH change. However incorporation of paddy straw in conjunction with N(60)P(60) and T. reesei inoculation resulted in maximum dehydrogenase, alkaline phosphatase and highest humus content of soil. Mixed inoculation of A. awamori and T. reesei did not prove effective in improving the soil biochemical properties in comparison to single inoculation of T. reesei. Results showed that in situ incorporation of paddy straw in combination with N(60)P(60) and T. reesei inoculation can be used as an effective measure for valuable disposal of paddy straw and to improve the soil health by reducing mineral fertilization.

Alkaline Phosphatase↗
PubMed2004

Enhanced degradation of fluorene in soil slurry by Absidia cylindrospora and maltosyl-cyclodextrin.

This study investigates the fungal biodegradation of fluorene, a polycyclic aromatic hydrocarbon, in liquid medium and soil slurry. Fungal strains and cyclodextrins were used in order to degrade fluorene and optimize fluorene bioavailability and degradation in soil slurries. After a procedure of selection in solid and liquid media, maltosyl-cyclodextrin, a branched cyclodextrin was chosen. 47 fungal strains isolated from a contaminated site were tested for biodegradation. Results showed the greater efficiency of "adapted" fungi isolated from contaminated soil vs reference strains belonging to the collection of the laboratory. These assays allowed us to select the most efficient strain, Absidia cylindrospora, which was used in a bioaugmentation process. Bioaugmentation tests were performed in an artificially contaminated non-sterile soil. In the presence of A. cylindrospora, more than 90% of the fluorene was degraded within 288 h, while 576 h were necessary in the absence of fungal bioremediation. It also appeared that biodegradation was enhanced by amendment with previously selected maltosyl-cyclodextrin. The results of this study indicate that A. cylindrospora and maltosyl-cyclodextrin could be used successfully in fluorene bioremediation systems.

Absidia↗
PubMedDate not supplied

Degradation/solubilization of Chinese lignite by Penicillium sp. P6.

Penicillium sp. P6, isolated from coal mine soil at the Qiantong colliery Liaoning Province, Northwest China, can degrade Chinese lignite in 36 h on a plate colony and in 48 h using a 4-day cultured cell-free filtrate. Results of elemental analysis and IR spectrometry indicated that solubilized products exhibited some alterations in comparison to the original lignite. The amount of fulvic acid extracted from the biodegraded lignite was high, and the molecular distribution of the humic acids from biodegraded lignite changed distinctively in comparison to which extracted from the control lignite, possibly due to the depolymerization associated with fungal biodegradation.

Benzopyrans↗
PubMed1995

Fungal colonization of synthetic substrates for use in space craft.

Materials being used or considered for use in space flights were examined for their susceptibility to fungal colonization. The materials included soft goods (clothing) and insulation and fabrication products such as Velcro attachments and elastic cord binders. Materials were exposed for at least 28 days in a high-humidity chamber colonized with over 50 species of fungi, including those species recommended for determining recalcitrance of materials to fungal biodegradation. At least nine of 25 products demonstrated extensive microscopic colonization by fungi, mostly by Acremonium obclavatum. Challenge procedures that rely on observations with the unaided eye, or 40 x magnification of growth by a restricted number of fungal species with a cellulosic substrate as a positive control, are insufficient for determining the resistance of synthetic substrates to fungal colonization.

Construction Materials↗
PubMed1998

Oxidative biodegradation of phosphorothiolates by fungal laccase.

Organophosphorus (OP) insecticides and nerve agents that contain P-S bond are relatively more resistant to enzymatic hydrolysis. Purified phenol oxidase (laccase) from the white rot fungus Pleurotus ostreatus (Po) together with the mediator 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) (ABTS) displayed complete and rapid oxidative degradation of the nerve agents VX and Russian VX (RVX) and the insecticide analog diisopropyl-Amiton with specific activity: k(sp) = 2200, 667 and 1833 nmol min(-1) mg(-1), respectively (pH 7.4, 37 degrees C). A molar ratio of 1:20 for OP/ABTS and 0.05 M phosphate at pH 7.4 provided the highest degradation rate of VX and RVX. The thermostable laccase purified from the fungus Chaetomium thermophilium (Ct) in the presence of ABTS caused a 52-fold slower degradation of VX with k(sp) = 42 nmol min(-1) mg(-1). The enzymatic biodegradation products were identified by 31P-NMR and GC/MS analysis.

Benzothiazoles↗
PubMed2006

Study of biodegradation products from azo dyes in fungal degradation by capillary electrophoresis/electrospray mass spectrometry.

Biodegradation products from four model sulfonated azo dyes Orange II, Acid Orange 8, Food Yellow 3, and 4-[(4-hydroxyphenyl)azo]-benzenesulfonic acid, sodium salt (4HABA), during fungal degradation were determined by capillary electrophoresis coupled with ion trap mass spectrometry (CE-MS) with electrospray ionization and a coaxial sheath flow interface. The development and optimization of this analytical method including the sheath liquid composition and flow rate, nebulizing gas flow rate, carrier electrolyte, and MS voltage are described herein. Detection of unknown biodegradation products was carried out under negative ion mode with base peak electrophorogram (BPE) or extractive ion electrophorogram (EIE) monitoring. A volatile ammonium acetate buffer (10 mM) without organic modifier and a shealth liquid made from 2-propanol and water (80:20, v/v) were suited for the separation and ESI interface. The sulfonated ion was the base peak for model azo dyes and their metabolites containing sulfonic group. Results showed that the tested azo dyes were degraded quickly in the culture of white rot fungus, Pleurotus ostreatus in 3 days with the major biodegradation products being 4-hydroxy-benzenesulfonic acid, 3-methyl-4-hydroxy-benzenesulfonic acid, benzenesulfonic acid, 1,2-naphthoquinone-6-sulfonic acid and 3-methyl-benzenesulfonic acid.

Azo Compounds↗
PubMed2000

Do the extracellular enzymes cellobiose dehydrogenase and manganese peroxidase form a pathway in lignin biodegradation?

The extracellular enzyme manganese peroxidase is believed to degrade lignin by a hydrogen peroxide-dependent oxidation of Mn(II) to the reactive species Mn(III) that attacks the lignin. However, Mn(III) is not able to directly oxidise the non-phenolic lignin structures that predominate in native lignin. We show here that pretreatment of a non-phenolic lignin model compound with another extracellular fungal enzyme, cellobiose dehydrogenase, allows the manganese peroxidase system to oxidise this molecule. The mechanism behind this effect is demethoxylation and/or hydroxylation, i.e. conversion of a non-phenolic structure to a phenolic one, mediated by hydroxyl radicals generated by cellobiose dehydrogenase. This suggests that cellobiose dehydrogenase and manganese peroxidase may act in an extracellular pathway in fungal lignin biodegradation. Analytical techniques used in this paper are reverse-phase high-pressure liquid chromatography, gas chromatography connected to mass spectroscopy and UV-visible spectroscopy.

Anisoles↗
PubMed2002

Fungal contribution to in situ biodegradation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) film in soil.

The contribution of fungi to the microbial degradation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) films in soil was studied. Various traces, cavities, and grooves observed on the dented surface of PHBV films demonstrated that the degradation was a concerted effect of a microbial consortium colonizing the film surface, including fungi, bacteria, and actinomycetes. The succession of microbial consortia in the soil around the PHBV films during the degradation showed a distinctive increase in the fungal population, resulting in its dominance. Comparison of the degradation ability of microbial strains isolated from soil where PHBV films were degraded, revealed that fungi showed the highest contribution to PHBV degradation, growing very rapidly along the film surface with their high degradation ability and then expanding their hyphae in a three-dimensional manner.

Bacteria↗
PubMed2006

The role of indigenous bacterial and fungal soil populations in the biodegradation of crude oil in a desert soil.

The biodegradation capacity of indigenous microbial populations was examined in a desert soil contaminated with crude oil. To evaluate biodegradation, soil samples supplemented with 5, 10 or 20% (w/w) of crude oil were incubated for 90 days at 30 degrees C. The effect of augmentation of the soil with vermiculite (50% v/v) as a bulking agent providing increased surface/volume ratio and improved soil aeration was also tested. Maximal biodegradation (91%) was obtained in soil containing the highest concentration of crude oil (20%) and supplemented with vermiculite; only 74% of the oil was degraded in samples containing the same level of crude oil but lacking vermiculite. Gas chromatograms of distilled fractions of crude oil extracted from the soil before and after incubation demonstrated that most of the light and part of the intermediate weight fractions initially present in the oil extracts could not be detected after incubation. Monitoring of microbial population densities revealed an initial decline in bacterial viable counts after exposure to oil, presumably as a result of the crude oil's toxicity. This decline was followed by a steep recovery in microbial population density, then by a moderate increase that persisted until the end of incubation. By contrast, the inhibitory effect of crude oil on the fungal population was minimal. Furthermore, the overall increased growth response of the fungal population, at all three levels of contamination, was about one order of magnitude higher than that of the bacterial population.

Aluminum Silicates↗
PubMed2002

Colorimetric assays for biodegradation of polycyclic aromatic hydrocarbons by fungal laccases.

Polycyclic aromatic hydrocarbons (PAHs) are highly toxic organic pollutants widely distributed in terrestrial and aquatic environments. In the present work, 2 colorimetric assays for laccase-catalyzed degradation of PAHs were developed based on studies of the oxidation of 12 aromatic hydrocarbons by fungal laccases from Trametes versicolor and Myceliophthora thermophila. Using a sodium borohydride water-soluble solution, the authors could reduce the single product of laccase-catalyzed anthracene biooxidation into the orange-colored 9,10-anthrahydroquinone, which is quantifiable spectrophotometrically. An assay using polymeric dye (Poly R-478) as a surrogate substrate for lignin degradation by laccase in the presence of mediator is also presented. The decolorization of Poly R-478 was correlated to the oxidation of PAHs mediated by laccases. This demonstrates that a ligninolytic indicator such as Poly R-478 can be used to screen for PAH-degrading laccases; it will also be useful in screening mutant libraries in directed evolution experiments. Poly R-478 is stable and readily soluble. It has a high extinction coefficient and low toxicity toward white rot fungi, yeast, and bacteria, which allow its application in a solid-phase assay format.

Anthracenes↗
PubMed1999

Biodegradation of pentachlorophenol (PCP) by white rot fungal strains screened from local sources and its estimation by high-performance liquid chromatography.

White rot fungal strains screened from local sources (wood trunks and from effluents of pulp and paper industry) were tested for their ability to biodegrade polymeric compounds, viz. polymeric dyes (crystal violet and brilliant green) and chlorinated phenol (pentachlorophenol). Two of the most promising strains showing maximum degradation of polymeric dyes were selected to study the biodegradation potential and pattern of biodegradation of pentachlorophenol (PCP), a commonly used leather preservative and a potential carcinogen. PCP was quantitatively estimated and analysed by high-performance liquid chromatography (HPLC). Conditions were optimized for the measurement of PCP on HPLC, which were: mobile phase, 60% acetonitrile and 40% water; flow rate, 1 mL/ min; column, mu Bondapack C18 RP and UV detector at 238 nm. One of the white rot fungal strains isolated from wood trunk showed a maximum 68% biodegradation of PCP in liquid-buffered medium in 16 days. The biodegradation pattern of PCP followed a pseudo-first-order kinetics. Studies on enhancement of biodegradation of polymeric dyes and PCP showed that the kinetics of biodegradation is greatly improved by the presence of manganese ions, H2O2 and glucose in the medium. This strongly suggests the involvement of peroxidase enzyme machinery of white rot fungus in the biodegradation process of PCP.

Biodegradation, Environmental↗
PubMed2005

Biodegradation of toluene by the new fungal isolates Paecilomyces variotii and Exophiala oligosperma.

Two new fungal strains, namely Paecilomyces variotii and Exophiala oligosperma, were isolated on toluene as the sole carbon and energy source, mineralizing the substrate into carbon dioxide. Fungal strains isolated so far on such a pollutant and completely degrading it are very scarce. Both fungi degraded the pollutant over the pH range 3.9-6.9 and temperature range 23-40 degrees C, but E. oligosperma was barely active at the highest temperature of 40 degrees C. Fungal growth on alkylbenzenes at 40 degrees C has not been reported before. Since the activity of the strains gradually decreased at pH values below 4.0, the use of nitrate instead of ammonium was tested. In the presence of toluene, nitrate was a suitable nitrogen source for the Exophiala strain, but not for the Paecilomyces strain. Nitrate rather than ammonium allowed the maintenance of a more constant pH.

Benzene↗
PubMed2024

Biochemical insights into the biodegradation mechanism of typical sulfonylureas herbicides and association with active enzymes and physiological response of fungal microbes: A multi-omics approach.

The extensive use of sulfonylurea herbicides has raised major concerns regarding their long-term soil residues and agroecological risks despite their role in agricultural protection. Microbial degradation is an important approach to remove sulfonylureas, whereas understanding the associated biodegradation mechanisms, enzymes, and physiological responses remains incomplete. Based on the rapid biodegradation of nicosulfuron by typical fungal isolate Talaromyces flavus LZM1, the dependency on cellular accumulation and environmental conditions, e.g. pH and nutrient supplies, was shown in the study. The biodegradation of nicosulfuron occurred intracellularly and followed the cascade of reactions including hydrolysis, Smile contraction rearrangement, hydroxylation, and opening of the pyrimidine ring. Besides 2-amino-4,6-dimethoxypyrimidine (ADMP) and 2-aminosulfonyl-N,N-dimethylnicotinamide (ASDM), numerous products and intermediates were newly identified and the structural forms of methoxypyrimidine and sulfonylurea bridge contraction rearrangement are predicted to be more toxic than nicosulfuron. The biodegradation should be enzymatically regulated by glycosylphosphatidylinositol transaminase (GPI-T) and P450s, which were manifested with the significant upregulation in proteomics. It is the first time that the hydrolysis of nicosulfuron into ADMP and ASDM have been associated with GPI-T. The integrated pathways of biodegradation were further elucidated through the involvement of various active enzymes. Except for the enzymatic catalysis, the physiological responses verified by metabolo-proteomics were critical not only to regulate material synthesis, uptake, utilization, and energy transfer but also to maintain antioxidant homeostasis, biodegradability, and tolerance of nicosulfuron by the differentially expressed metabolites, such as acetolactate synthase and 3-isopropylmalate dehydratase. The obtained results would help understand the biodegradation mechanism of sulfonylurea from chemicobiology and enzymology and promote the use of fungal biodegradation in pollution rehabilitation.

Herbicides↗
PubMed2006

Biodegradation of synthetic polymers by composting and fungal treatment.

Two types of copolymers--poly(ester-amide)s--by the anionic copolymerization of epsilon-caprolactam and epsilon-caprolactone, and aromatic-aliphatic copolyesters based on glycolyzed polyethylene terephthalate from used beverage bottles and epsilon-caprolactone were prepared. Biodegradation tests of these copolymers were performed by two methods, viz. composting under controlled conditions and treatment with ligninolytic fungi. Both methods resulted in degradation of the copolymers, composting being more robust. Out of fungal strains tested Inonotus hispidus degraded aromatic-aliphatic copolyesters most intensively.

Basidiomycota↗