Degradation of chloronitrobenzenes by a coculture of Pseudomonas putida and a Rhodococcus sp.

A single microorganism able to mineralize chloronitrobenzenes (CNBs) has no t been reported, and degradation of CNBs by coculture of two microbial stra ins was attempted. Pseudomonas putida HS12 was first isolated by analogue e nrichment culture using nitrobenzene (NB) as the substrate, and this strain was observed to possess a partial reductive pathway for the degradation of NE. From high-performance liquid chromatography-mass spectrometry and H-1 nuclear magnetic resonance analyses, NB-grown cells of P. putida HS12 were found to convert 3- and 4-CNBs to the corresponding 5- and 4-chloro-2-hydro acetanilides, respectively, by partial reduction and subsequent acetylation , For the degradation of CNBs, Rhodococcus sp, strain HS51, which degrades 4- and 5-chloro-2-hydroxyacetanilides, was isolated and combined with P. pu tida HS12 to give a coculture. This coculture was confirmed to mineralize 3 - and 4-CNBs in the presence of an additional carbon source. A degradation pathway for 3- and 4-CNBs by the two isolated strains was also proposed.