Enhanced biodegradation of polychlorinated biphenyls by defined bacteria-yeast consortium

In the present study, a defined consortium of Pseudomonas sp. MO2A and Debaryomyces maramus CW36 was studied to assess their potential for enhancing degradation and detoxification of polychlorinated biphenyls (PCBs) in liquid medium. The optimum pH of the medium was 6.0 for PCB degradation by the consortium. At this pH, the coculture of the bacterium and the yeast showed promoted PCB degradation (69.6 % in 14 days) under aerobic conditions. Under the same conditions, Pseudomonas sp. MO2A and Debaryomyces maramus CW36 showed only 57.0 and 27.8 % degradation of PCBs, respectively. The addition, appropriate amounts of glucose or biphenyl could enhance PCB biodegradation. However, Tween 80 showed no stimulatory effect on PCB biodegradation at any level applied (5-30 mg/L). The highest removal and dechlorination efficiencies of PCBs were 92.6 and 61.4 %, respectively, on the 14th day using the coculture. The results of toxicity studies suggested that this consortium may be effectively used for detoxification of PCBs due to their complementary role in degradation of toxic intermediates. Our results showed that the use of bacteria-yeast coculture was more effective for PCB degradation than any single culture and has potential environmental implications in cleaning up PCB polluted environments.