BIOTRANSFORMATION OF S-TRIAZINE HERBICIDES AND RELATED DEGRADATION PRODUCTS IN LIQUID CULTURES BY THE WHITE-ROT FUNGUS PHANEROCHAETE-CHRYSOSPORIUM

The ability of the white rot basidiomycete Phanerochaete chrysosporium to transform s-triazine herbicides has been investigated in laborator y experiments. The chlorinated metabolites formed during atrazine N-de alkylations were not further transformed by the fungus, whereas hydrox yatrazine was converted to an unknown product. P. chrysosporium was al so able to carry out the N-dealkylation of the herbicides simazine, pr opazine and terbuthylazine. Herbicide metabolism was not supported by purified peroxidases. The highest rates of herbicide N-dealkylation we re obtained in liquid cultures maintained under moderate temperature a llowing a long mycelium growing phase. Atrazine transformation was fou nd to be supported by the mycelium, which contained significant amount s of microsomal cytochrome P450. Herbicide N-dealkylation was decrease d in the presence of 1-aminobenzotriazole, in agreement with the invol vement of P450 monooxygenases in atrazine metabolism.