Metabolism of dinitrotoluene isomers by Escherichia coli isolated from human intestine.

Abstract

Technical grade dinitrotoluene (DNT), an important industrial nitroaromatic compound, not only induces methemoglobinemia but is a potent hepatocarcinogen in man and rats. The purpose of the present study was to identify the metabolites produced from five DNT isomers (2, 3-, 2, 4-, 2, 5-, 2, 6-and 3, 4-DNT) by Escherichia coli (E. coli) strain W3110, isolated from human intestine. Data obtained from thin-layer and gas chromatographies or liquid scintillation counting indicated that the metabolites produced by the E. coli were two monoaminonitrotoluenes and hydroxylaminonitrotoluenes in all cases. This finding indicates that DNT is reduced via hydroxylaminonitrotoluenes to monoaminonitrotoluenes in E. coli. In addition, it was found that the reduction reactivities of DNT isomers were 3->2-for 2, 3-DNT, 4->2-for 2, 4-DNT, 5->2-for 2, 5-DNT and 3->4-for 3, 4-DNT. The role of bacterial reduction in the toxic actions of DNT is discussed.