Isolation of nitrobenzene degrading strain Pseudomonas NB001 and application in the bioremediation of polluted water body

Abstract

A bacterium using nitrobenzene (NB) as a sole source of carbon, nitrogen and energy was isolated from NB-contaminated water body by the enrichment technology. It was identified as Pseudomonas NB001 by the phylogenetic analysis based on 16S rDNA sequence and the biochemical and physiological characteristics. Degradation of NB by strain NB001 was concomitant with the release of nitrite. Activities of catechol2,3-dioxygenase in strain NB001 cells grown in the culture fluid were higher than that in cells under any other conditions (P < 0.05). Under the pure culture conditions, 98.4% of NB at initial concentration of 50 mg L−1 was removed in 136 hours. Glucose at starting concentration of 100 mg L−1 delayed the onset of the exponential phase of NB degradation and weakened the degradation ability of per cell in the pure culture systems. In the river water, 89.5% of NB was degraded in 8 days. Suspended matter obviously increased the degradation rate of NB in the early stages, but decreased in the final stages. Cd2+ and Hg2+ significantly weakened the ability of the strain to degrade NB at initial concentrations of 10.0 mg L−1 and 5.0 mg L−1, respectively. The results would offer useful information for the application of strain NB001 in the bioremediation or the control of NB-contaminated environment.