A NOVEL PATHWAY FOR THE BIODEGRADATION OF 3-NITROTOLUENE IN PSEUDOMONAS-PUTIDA

3-Nitrotoluene was degraded when incubated with the resting cells of P seudomonas putida OU83. Most of the 3-nitrotoluene (70%) was metaboliz ed via reduction of the nitro group to form 3-aminotoluene (3-AT). A m inor portion (30%) was degraded through a novel pathway involving oxid ation of 3-NT to form 3-nitrophenol through a series of intermediary m etabolites: 3-nitrobenzyl alcohol, 3-nitrobenzaldehyde and 3-nitrobenz oic acid. Degradation of 3-nitrophenol occurred with the formation of a transient intermediary metabolite, hydroxynitroquinone, which was fu rther degraded with the near stoichiometric release of nitrite into th e medium. 3-Nitrotoluene-induced cells showed increased oxygen consump tion with 3-nitrotoluene, 3-nitrobenzaldehyde, 3-nitrobenzoate, and 3- nitrophenol as substrates in comparison to uninduced cells. Cell extra cts prepared from strain OU83 contained benzylalcohol dehydrogenase an d benzaldehyde dehydrogenase activities. The experimental evidence sug gests a novel pathway for the degradation of 3-NT in which C-1 elimina tion is catalyzed by a cofactor-independent deformylase, rather than a decarboxylase or dioxygenase.