Ceriporiopsis subvermispora, a specific lignin-degrading fungus produced free unsaturated fatty acids (USFAs) including 9,12-octadecaienoic asid, together with saturated fatty acids (SFAs) at an incipient stage of cultivation on wood meal cultures. In prolonged cultivation period after two weeks, the amount of intact fatty acids decreased with increasing in organic hydroperoxide and TBARS production. To analyze the free radical reactions of linoleic acid with MnP, the fungal metabolite was reacted with MnP from C. subvermispora and the radicals produced were analyzes by ESR. The in vitro spectroscopic analysis demonstrated that MnP-dependent lipid peroxidation is not initiated by direct ion of hydrogen from bis-allylic position during turnover but proceeds by a Mn(III)-dependent hydrogen ion from enols and subsequent propagation reactions involving the formation of acyl radical from lipid hydroperoxid. This finding expands the role of chelated Mn(III) from a phenol oxidant to a strong generator of free radicals from lipids and lipid hydroperoxides in lignin biodegradation. Possible roles of the free radical reactions in selective lignolysis is discussed.

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