Isolation and characterization of polychlorinated biphenyl-degrading bacterium

Two polychlorinated biphenyls-degrading bacteria were isolated from long-term PCBs-contaminated soil using biphenyl as carbon source and energy source. These halophilic bacterial strains were separated, purified and enriched. After morphological observation and dye identification, the mixed fermentation was selected for the experiments about influence on degrading polychalorinated biphenyls at last. The optimal experimental conditions of PCBs-degrading were obtained according to the changes of pH, temperature, inoculation amount and liquid medium. The results indicated that the degradation ratio could reach to 70% when the temperature was 30 ℃, pH was7.0, inoculation amount was OD600nm =1.0, and liquid medium was 10.00 mL. Results from surfactants efficiency degradation proved that the mixed surfactants in low concentrations(500 mg/L) could promote the degradation and high concentrations(700 mg/L) could suppress the degradation. The degradation ratio could reach to 91.5% after 16 d when mixed surfactants(300 mg/L) were added to the degradation system.