Biodegradation of PCB congeners by white rot fungus,<i>Ceriporia</i>sp. ZLY-2010, and analysis of metabolites

Abstract

Polychlorinated biphenyls (PCBs) are difficult to degrade due to poor solubility, toxicity, and thermal stability. In the present study, the feasibility of PCB congener biodegradation by Ceriporia sp. ZLY-2010 was evaluated. The biodegradation rates of four PCB congeners, 4,4'-dichlorobiphenyl, 2,3',4',5-tetrachlorobiphenyl, 2,2',4,5,5'-pentachlorobiphenyl, and 2,2',4,4',5,5'-hexachlorobiphenyl were evaluated. The degradation rate of 4,4'-dichlorobiphenyl was 34.03% on incubation day 13, while that of 2,2',4,4',5,5'-hexachlorobiphenyl reached 40.05% on incubation day 17. Therefore, Ceriporia sp. ZLY-2010 was degrading the higher PCB congeners more efficiently. PCB congener degradation products were extracted using acetone and ethyl acetate. No 2,2',4,5,5'-pentachlorobiphenyl metabolites were detected in Ceriporia sp. ZLY-2010 culture, whereas 2,2',4,4',5,5'-hexachlorobiphenyl appeared to degrade to benzoic acid. However, intermediates of 2,2',4,4',5,5'-hexachlorobiphenyl were not detected during degradation. Therefore, additional studies should be performed to explore the mechanisms of PCB degradation. Our results indicate that Ceriporia sp. ZLY-2010 is able to degrade highly chlorinated biphenyls and has potential for use in PCB biodegradation and bioremediation.