生物强化膜生物反应器(MBR)处理邻苯二甲酸二乙酯(DEP)效果及微生物群落结构分析

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

为强化邻苯二甲酸二乙酯(DEP)降解,将从活性污泥中分离的高效DEP降解菌Arthrobacter sp.LMS13运用到MBR反应器,考察强化系统对DEP去除效果,并通过实时荧光定量(q-PCR)和Illumina Mi Seq技术分别对系统运行期间邻苯二甲酸双加氧酶降解基因(phtA)数量以及微生物群落结构特征进行了分析.结果表明,强化系统能加快反应器启动,对进水浓度为800 mg·L-1的DEP,强化系统和未经强化系统在运行后期(61 d)对DEP平均去除率分别为81%和19%.q-PCR结果显示,在驯化阶段,phtA基因拷贝数上升,但当DEP浓度大于400 mg·L-1时,phtA基因数量下降;phtA基因拷贝数与DEP降解率呈正相关.Mi Seq测序结果进一步表明,高浓度DEP导致系统中群落多样性指数下降,但对强化系统多样性影响相对较小.反应器运行过程中,原活性污泥中占有较高比例的拟杆菌门(Bateroidetes)和厚壁菌门(Firmicutes)丰度降低,ε-变形纲(ε-Proteobacteria)、绿弯菌门(Chloroflexi)在反应系统中逐渐被淘汰,而β-变形纲(β-Proteobacteria)和放线菌门(Actinobacteria)成为系统中的优势菌门,其中红环菌属(Rhodocyclus)、博得氏杆菌属(Bordetella)、节杆菌属(Arthrobacter)为优势菌属,在DEP降解系统中起着主要作用,是保证DEP生物处理效果和维持反应器稳定运行的重要菌属.

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 Mi Seq 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 startup time,and the DEP removed rate of bioaugmented system and unbioaugmented system was 81% and 19%,at concentration of 800mg·L- 1,respectively. Pht A 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.