[Isolation and characterization of a sodium dodecyl benzene sulfonate degrading bacterial strain]

A bacterial strain, designated as WZR-A, which could utilize sodium dodecyl benzene sulfonate (SDBS) as sole carbon and energy source for growth, was isolated from contaminated river. The strain was identified as Ochrobactrum anthropi based on its morphological and physiological properties, and 16S rDNA sequence analysis. The optimum pH and temperature for cell growth and SDBS degradation were 7.0 and 30 degrees U, respectively. The degradation rate of SDBS by strain WZR-A was higher than 80% when its concentration was lower than 400mg/L. The results of whole cell protein SDS-PAGE electrophoresis showed that there were very obvious differences in the total cell protein composition of the strain between before and after SDBS induction. The enzyme distribution experiment showed that the enzymes relative SDBS degradation in the bacterium was intracellular one. Results from the characterization of degradation substrates together with the detection of activities of relative catabolic enzymes in crude extracts indicated that the aromatic ring cracking of SDBS by the strain probably via the modified ortho cleavage pathway and the strain could use broader spectrum substrates. A large plasmid was detected by utilizing plasmid isolating and curing technique and it was found that the genes involved in SDBS degradation were likely located on the plasmid.