Degradation by white-rot fungi

Figure 1. /3-0-4 lignin substructure model dimers 1-4 and their degradation by white-rot fungi, Phanerochaete chrysosporium, Coriolus versicolor, and Coriolus hirsutus. The ether bond between the C/ and the B-aromatic nucleus is referred to as /3-0-4 bond in lignin chemistry. 

R ten Have, PJM Teunissen. Oxidative mechanisms involved in lignin degradation by white-rot fungi. Chemical Reviews 101 3397-3413, 2001. 

Other organophosphonates, often also carrying sulfur substituents at the phosphoms atom, are used as pesticides [43]. Their degradation by white-rot fungi has been studied in some detail, but little is known about the chemistry of cleavage of C-P linkages in these compounds [43]. 

Kirk T K, Cullen D (1998), Enzymology and molecular genetics of wood degradation by white-rot fungi , in Young R A and Akhtar M, Environmentally friendly technologies for the pulp and paper industry. New York, John Wiley Sons, Inc., 273-307. 

Zadrazil, R, Galleti, G. C., Piccaglia, R., Chiavari, G., Francioso, O. (1991). Influence of oxygen and carbon dioxide on cell wall degradation by white-rot fungi. Anim. Feed Sci. Technol., 32,137-142. 

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). 

Regarding the degradation of PBDEs by white-rot fungi, the first evidence of their ability to degrade a PBDE compound corresponds to a study published by Hundt et al. [27], which studied the degradation of 4-bromo-BDE by Trametes versicolor. The degradation occurs initially by hydroxylation reaction with the possible formation of three different isomers of hydroxy-diphenyl ether followed... 

Ishikawa, H., W. J. Schubert, and F. F. Nord The Enzymatic Degradation of Softwood Lignin by White Rot Fungi. The Degradation by Polyporus versicolor and Forties fomentarius of Aromatic Compounds Structurally Related to Softwood Lignin. Arch. Biochem. Biophys. 100, 131-149 (1963). 

Thus, most of the degradative reactions of polymeric lignins suggested previously by the analysis of decayed lignin isolated from decayed wood by white-rot fungi were catalyzed by lignin peroxidase. 

Zeddel, A., Majcherczyk, A. Huttermann, A. (1994). Degradation and mineralization of polychlorinated biphenyls by white-rot fungi in solid-phase and soil incubation experiments. In Bioremed tation of Chlorinated and Polycyclic Aromatic Hydrocarbon Compounds, ed. R. E. Hinchee, A. Leeson, L. Semprini S. K. Ong, pp. 436-40. New York Lewis Publishers. 

The effect of PCDDs, PCDFs, and PCDDs on CP-degrading microorganisms in soil has not been systematically studied. These compounds do not biodegrade and do not seem to inhibit CP bioremediation (Valo Salkinoja-Salonen, 1986 McBain et al., 1995). The treatment of soils contaminated simultaneously with PAHs and chlorinated dimeric compounds by white-rot fungi could be potentially advantageous since the peroxidase enzymes oxidize all these chemicals (e.g. Valli et al., 1992 Gold et al., 1994 Lamar Glaser, 1994). 

Table 8.8. Degradation of chlorophenols in soil by white rot fungi... 

Peroxidases are encoded by large multi-gene families, which has complicated the study of individual peroxidase enzymes (cf Christensen et al., 1998). Manganese and diarylpropane peroxidases are used by white rot fungi (basiodiomycetes) to degrade lignin via oxidation. 

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