Fungi white rot

The mechanism and enzymology of transformations by white-rot fungi are complicated for several issues  

A brief summary of these factors includes the following issues  

Monooxygenases. Under nonlignolytic conditions, arene monooxygenase and epoxide hydrolase systems may function to produce trani-dihydrodiols. Hydrogen abstraction mediated by the lipid peroxidase system may operate, for example, in the formation of fluorene-9-one from fluorene by Ph. chrysosporium (Bogan et al. 1996). 

Hydroxylases. Some substrates are activated to cation radicals that react further with H2O to ultimately produce quinones. This is particularly prevalent in 4- and 5-ring compounds, though important alternatives exist. 

Dioxygenase. Although it is not involved in the transformation of PAHs, it may be noted for the sake of completeness that a catechol intradiol dioxygenase is involved in the fission of 1,2,4-trihydroxybenzene that is formed from a number of aromatic substrates (Rieble et al. 1994). 

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The metabolic activity of other white-rot fungi including Phanerochaete chrysosporium and Pleurotus ostreacus has been discussed in the context of polycyclic aromatic hydrocarbons. For example, the mineralization potential of the manganese peroxide system fmmNematolomafrowardii for a number of substrates has been demonstrated (Hofrichter et al. 1998) the formation of CO2 from labeled substrates ranged from 7% (pyrene) to 36% (pentachlorophenol), 42% (2-amino-4, 6-dinitrotoluene), and 49% (catechol). 

Beaudette LA, S Davies, PM Fedorak, OP Ward, MA Pickard (1998) Comparsion of gas chromatography and mineralization experiments for measuring loss of selected polychlorobiphenyl congeners in cultures of white rot fungi. Appl Environ Microbiol 64 2020-2025. 

Extracellnlar H2O2 is required for the activity of peroxidases in white-rot fungi, and this can be prodnced by several fungal reactions ... 

Bonnarme P, TW Jeffries (1990) Mn(ll) regulation of lignin peroxidases and manganese-dependent peroxidases from lignin-degrading white-rot fungi. Appl Environ Microbiol 56 210-217. 

Although a number of white-rot fungi have been examined and shown to degrade PAHs (Field et al. 1992), greatest attention has probably been directed to Phanerochaete chrysosporium and Pleurotus ostreatus, and to the PAHs anthracene, phenanthrene, pyrene, and benzo[a]pyrene that will be used to illustrate the cardinal principles. A substantial fraction of PAHs may also be sorbed to the biomass—40% for phenanthrene and 22% for benzo[a]pyrene (Barclay et al. 1995). The degree of mineralization of PAHs by white-rot fungi may sometimes be quite low, for example, for Pleurotus ostreatus, yields were 3.0, 0.44, 0.19, and 0.19% for phenanthrene, pyrene, fluorene, and benzo[a]pyrene, respectively (Bezalel et al. 1996a). 

Field JA, E de Jong, GF Costa GF, JAM de Bont (1992) Biodegradation of polycyclic aromatic hydrocarbons by new isolates of white-rot fungi. Appl Environ Microbiol 58 2219-2226. 

Barr DP, SD Aust (1994) Mechanisms white rot fungi use to degrade pollutants. Environ Sci Technol 28 78A-87A. 

Shah MM, DP Barr, N Chung, SD Aust (1992) Use of white rot fungi in the degradation of environmental chemicals. Toxicol Lett 64 493-501. 

Andersson BE, T Henrysson (1996) Accumulation and degradation of dead-end metabolites during treratment of soil contaminated with polycyclic aromatic hydrocarbons with five strains of white-rot fungi. Appl Microbiol Biotechnol 46 647-652. 

Walter, M., Boul, L., Chong, R., and Ford, C., Growth substrate selection and biodegradation of PCP by New Zealand white-rot fungi, J. Environ. Manage., 71, 361-369, 2004. 

Keywords Biodegradation, Emerging pollutants, Sewage sludge, Trametes versicolor, White-rot fungi... 

The concept of developing a technology for the environmental application of fungi, particularly white-rot fungi (WRF) appeared in the 1980s [1], Since then, the development of biotechnologies using WRF has been studied to treat a wide variety... 

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