Transformation and tolerance of TNT (2,4,6-trinitrotoluene) by fungi

Eight fungi were tested for the ability to transform and tolerate TNT (2,4,6-trinitrotoluene) in liquid culture. In contrast to most previous studies, we used high concentrations of TNT (200 ppm), short incubation times, nonlignolytic conditions and taxonomically diverse fungi. Virtually no TNT was detectible in cultures of Cladosporium resinae and Cunninghamella echinulata var. elegans after three days growth. All fungi produced azoxy-tetranitrotoluene, amino-dinitrotoluene and hydroxylamino-dinitrotoluene metabolites. The fate of [C-14]TNT fed to cultures was followed. Cunninghamella echinulata var. elegans, Trichoderma viride, Schizophyllum commune and Cladosporium resinae converted significant amounts (27%, 19%, 18% and 8%, respectively) to aqueous-soluble metabolites. No fungi produced (CO2)-C-14 or C-14-volatile metabolites. Trichoderma viride and C. resinae were most tolerant of TNT, as determined by the inhibition of radial growth on agar. Imperfect fungi, native to soil and able to tolerate TNT and transform it rapidly, could be used to increase the efficiency of mineralization of TNT by Phanerochaete chrysosporium. (C) 1997 Elsevier Science Limited.