CATABOLISM OF 3-NITROPHENOL BY RALSTONIA-EUTROPHA JMP-134

Ralstonia eutropha JMP 134 utilizes 3-nitrophenol as the sole source o f nitrogen, carbon, and energy. The entire catabolic pathway of 3-nitr ophenol is chromosomally encoded. An initial NADPH-dependent reduction of 3-nitrophenol was found in cell extracts of strain JMP 134. By use of a partially purified 3-nitrophenol nitroreductase from 3-nitrophen ol-grown cells, 3-hydroxylaminophenol was identified as the initial re duction product. Resting cells of R. eutropha JMP 134 metabolized 3-ni trophenol to N-acetylaminohydroquinone under anaerobic conditions. Wit h cell extracts, 3-hydroxylaminophenol was converted into aminohydroqu inone. This enzyme-mediated transformation corresponds to the acid-cat alyzed Bamberger rearrangement, Enzymatic conversion of the analogous hydroxylaminobenzene yields a mixture of 2- and 4-aminophenol.