PRIMARY AND SECONDARY METABOLISMS OF WHITE-POCKET FUNGUS

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Catalysis which could lead to the degradation of environmentally persistent pollutants in an effective and safe manner were researched. Recently, white-rot basidiomycetes have been studied by many research groups since only this type of fungi can cause the complete mineralization of lignin, an aromatic polymer. However, powerful lignin degraders secretes phenol oxidizing enzymes such as laccase and manganese peroxidase, which react with phenolic substrates forming not only degradation products but also polymerized products. In this study, target reaction was degradation of chlorinated phenols without any polymerization reactions forming the chlorinated aromatic polymers. To achieve this, white-rot fungi which show weak actvity against lignin degradation and brown-rot fungi which has been known not to degrade lignin were utilized. Some interesting and unique results are listed below :(1) White-rot fungus, Fomitella fraxinea did not seceretes any phenol oxidases during decolorization of dye and lignin degradation under any conditions examined so far.(2) Dye-decolorization activity was found in the culture filtrate of F.fraxinea.(3) Brown-rot fungi were capable of mineralizing either phenolic or nonphenolic monomers with the oxidation and reduction of alkyl side chain and the hydroxylation of aromatic rings.(4) Brown-rot fungi did not cause polymerization of phenolic substrates.