Title Simultaneous Utilization of Two Different Pathways in Degradation of 2,4,6-Trinitrotoluene by White Rot Fungus Irpex lacteus
Author Hyoun-Young Kim, and Hong-Gyu Song *
Address Division of Biological Sciences, Kangwon National University, Chuncheon 200-701, Korea
Bibliography Journal of Microbiology, 38(4),250-254, 2000,
Key Words trinitrotoluene, Irpex lacteus, metabolic pathway, nitroreductase, hydride-Meisenheimer complexes
Abstract This study confirmed that white rot fungus Irpex lacteus was able to metabolize 2,4,6-trinitrotoluene (TNT) with two different initial transformations. In one metabolic pathway of TNT a nitro group was removed from the aromatic ring of TNT. Hydride-Meisenheimer complexes of TNT (H^- -TNT), colored dark red, were confirmed as the intermediate in this transformation by comparison with the synthetic compounds. 2,4-Dinitrotoluene as a following metabolic product was detected, and nitrite produced by denitration of H^- -TNT supported this transformation. In the other TNT pathway, nitro groups in TNT were successively reduced to amine groups via hydroxylamines. Hydroxylamino-dinitrotoluenes and amino-dinitrotoluenes were identified as the intermediates. The activity of a membrane-associated aromatic nitroreductase was detected in the cell-free extract of I. lacteus. This enzyme catalyzed the nitro group reduction of TNT with NADPH as a cofactor. Enzyme activity was not observed in the presence of molecular oxygen.
Download PDF 384-09.pdf