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 5 DNT isomers (2,3- 2,4-, 2,5-, 2,6- and 3,4-DNT) by Escherichia 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 2 monoaminonitrotoluenes and hydroxylamino-nitrotoluenes in all cases. DNT is evidently reduced via hydroxylaminonitrotoluenes to monoaminonitrotoluenes in E. coli. 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.