[Performance and Microbial Community Analysis of Bioaugmented Treatment of Diethyl Phthalate (DEP) in Membrane Bioreactor].

To enhance the degradation of DEP, the DEP-degrading bacterium Arthrobacter sp. LMS13 isolated from activated sludge was inoculated in MBR reactor to investigate the DEP removal efficiency. At the same time, the real-time quantitative PCR and Illumina MiSeq high-throughput sequencing techniques were employed to detect the changes of phthalate dioxygenase gene (phtA) and the bacterial community structure in the process of reactor operation. The results showed that bioaugmented system shortened the start-up time, and the DEP removed rate of bioaugmented system and unbioaugmented system was 81% and 19%, at concentration of 800 mg·L-1, respectively. PhtA copies increased during domestication, but dropped when DEP concentration exceeded 400 mg·L-1. The phtA gene abundance and DEP removal rate were positively correlated. Bacteria community analysis showed that, along with the operation of reactor, the abundance of phylum of Bateroidetes and Firmicutes reduced, ε-Proteobacteria and Chloroflexi gradually disappeared in the system; on the contrary, β-Proteobacteria and Actinobacteria became the dominant phyla in reactor. Rhodocyclus, Bordetella and Arthrobacter were dominant in the DEP degradation system, and probably maintained the stable operation of reactor.