The toxic and recalcitrant polychlorinated biphenyls （PCBs） adversely affect human and biota by bioaccumulation and biomagnification through food chain. In this study, an anaerobic microcosm was developed to extensi...The toxic and recalcitrant polychlorinated biphenyls （PCBs） adversely affect human and biota by bioaccumulation and biomagnification through food chain. In this study, an anaerobic microcosm was developed to extensively dechlorinate hexa- and hepta-CBs in Aroclor 1260. After 4 months of incubation in defined mineral salts medium amended PCBs （70μmol· L^-1） and lactate （10 mmol· L^-1）, the culture dechlorinated hexa-CBs from 40.2% to 8.7% and hepta-CBs 33.6% to 11.6%, with dechlorination efficiencies of 78.3% and 65.5%, respectively （all in moL ratio）. This dechlorination process led to tetra-CBs （46.4%） as the predominant dechlorination products, followed by penta- （22.1%） and tri-CBs （5.4%）. The number of meta chlorines per biphenyl decreased from 2.50 to 1.41. Results of quantitative real-time PCR show that Dehalococcoides cells increased from 2.39 × 10^5±0.5× 10^5 to 4.99 ×10^7±0.32 ×10^7 copies mL^-1 after 120 days of incubation, suggesting that Dehalococcoides play a major role in reductive dechlorination of PCBs. This study could prove the feasibility of anaerobic reductive culture enrichment for the dehalogenation of highly chlorinated PCBs, which is priorto be applied for in situ biorernediation of notorious halogenated compounds.展开更多
基金Acknowledgements This work was financial supported by grants from the National Natural Science Foundation of China （Grant Nos. 51108014 and 41671310）.
文摘The toxic and recalcitrant polychlorinated biphenyls （PCBs） adversely affect human and biota by bioaccumulation and biomagnification through food chain. In this study, an anaerobic microcosm was developed to extensively dechlorinate hexa- and hepta-CBs in Aroclor 1260. After 4 months of incubation in defined mineral salts medium amended PCBs （70μmol· L^-1） and lactate （10 mmol· L^-1）, the culture dechlorinated hexa-CBs from 40.2% to 8.7% and hepta-CBs 33.6% to 11.6%, with dechlorination efficiencies of 78.3% and 65.5%, respectively （all in moL ratio）. This dechlorination process led to tetra-CBs （46.4%） as the predominant dechlorination products, followed by penta- （22.1%） and tri-CBs （5.4%）. The number of meta chlorines per biphenyl decreased from 2.50 to 1.41. Results of quantitative real-time PCR show that Dehalococcoides cells increased from 2.39 × 10^5±0.5× 10^5 to 4.99 ×10^7±0.32 ×10^7 copies mL^-1 after 120 days of incubation, suggesting that Dehalococcoides play a major role in reductive dechlorination of PCBs. This study could prove the feasibility of anaerobic reductive culture enrichment for the dehalogenation of highly chlorinated PCBs, which is priorto be applied for in situ biorernediation of notorious halogenated compounds.
