Biodegradation of CP/TCP by a constructed microbial consortium after comparative bacterial community analysis of long-term CP domesticated activated sludge

Abstract

The objective of this study was to construct a microbial consortium for effective biodegradation of chlorpyrifos (CP) and its hydrolysis product, 3,5,6-Trichloro-2-pyridinol (TCP). A activated sludge from an organophosphorus pesticide factory was domesticated under long-term (20 weeks) CP stress, and the dynamic change in bacterial communities was analyzed by high-throughput sequencing. Then, a microbial consortium MC-BSPK was constructed of Bacillus sp. MC-B, Serratia sp. MC-S, Pseudomonas sp. MC-P, and Klebsiella sp. MC-K, which were significantly enriched during the domestication process. The biodegradation capacities of the microbial consortium MC-BSPK reached 100% for CP within 9 days and 88.61% for TCP within 15 days under the optimized degradation conditions (pH 8.0 and 31 °C). High-performance liquid chromatography (HPLC) revealed that CP could be degraded by the microbial consortium MC-BSPK into TCP, probably through hydrolysis of the P–O ester bond, and further degraded into other small molecules. A bioassay revealed that the virulence of CP toward Drosophila melanogaster W1118 was clearly reduced by the microbial consortium MC-BSPK biodegradation. Thus, the easily constructed microbial consortium MC-BSPK with high CP/TCP degradation capacities has the potential for application in pesticide-contaminated bioremediation.