INHIBITION OF THE LIGNIN PEROXIDASE OF PHANEROCHAETE-CHRYSOSPORIUM BYHYDROXYLAMINO-DINITROTOLUENE, AN EARLY INTERMEDIATE IN THE DEGRADATION OF 2,4,6-TRINITROTOLUENE

The ability of the white rot fungus Phanerochaete chrysosporium to min eralize 2,4,6-trinitrotoluene (TNT) was studied in the concentration r ange of 0.36 to 20.36 mg/liter. The initial rate of (CO2)-C-14 formati on was 30% in 4 days at 0.36 mg of [C-14]TNT per liter and decreased t o 5% in 4 days at 20.36 mg of [C-14]TNT per liter. Such a pronounced i nhibition was not observed when a mixture of [C-14]2-amino-4,6-dinitro toluene and [C-14]4-amino-2,6-dinitrotoluene was used as a substrate. 2-Hydroxylamino-4,6-dinitrotoluene and its isomer 4-hydroxylamino-2,6- dinitrotoluene were identified as the first detectable degradation pro ducts of TNT. Their transient accumulation correlated with the inhibit ion of TNT degradation and of the veratryl alcohol oxidase activity of lignin peroxidase. With purified lignin peroxidase H8, it could be sh own that the two isomers of hydroxylamino-dinitrotoluene were oxidized by lignin peroxidase. The corresponding nitroso-dinitrotoluenes appar ently were formed, as indicated by the formation of azoxy-tetranitroto luenes.