不同污泥龄膜生物反应器内微生物的群落结构特征

为研究不同污泥龄MBR(膜生物反应器)内的微生物群落结构特征,构建了SRT(污泥龄)分别为10、20、40和80 d的4个平行的MBR,通过PCR-DGGE技术获得各MBR内微生物的DNA指纹图谱,并对条带进行切胶测序. 结果表明,SRT不影响MBR对废水的处理效果,不同SRT下MBR对NH₄+-N和COD_Cr的去除率均能达到90%以上. DGGE结果表明,在运行过程中,各MBR内的微生物群落结构均发生了明显变化,并且不同SRT的MBR内总细菌群落结构变化特征相同；SRT影响同一微生物在各MBR中的出现速率；总细菌Shannon-Wiener多样性指数和丰富度指数均随着SRT的增加而升高,SRT为80 d的MBR内Shannon-Wiener多样性指数最高. 测序结果表明,不同SRT的MBR内的优势种属不同,其中Arcobacter sp.、beta proteobacterium及Thiothrix sp.为不同SRT的MBR中共同存在的关键菌属,对MBR的运行起着重要作用. 

Characteristics of Microbial Community Structure in Membrane Reactors under Different Solid Retention Times

In order to characterize the microbial community structure in membrane reactors (MBRs) under different solid retention times (SRT), four parallel lab-scale MBRs were operated at SRT 10,0, 40 and 80 d. DNA fingerprinting was analyzed by PCR-DGGE and excised for band sequencing. The results showed that the SRT did not influence the performance of MBR to treat the wastewater. All four MBRs were able to remove more than 90% of NH₄+-N and COD_Cr. The results of DGGE indicated that the microbial community in MBRs changed obviously over the whole operation. The bacterial community structure changed in the same way in MBRs at different SRTs. The apparent speed of the same microorganism in MBRs was affected by SRT. The Shannon-Wiener diversity index and richness value all increased as the SRT increased, while the microbial diversity index at SRT 80 d was the highest among the four MBRs. Sequencing results showed that the advantageous species in MBR operated at different SRTs were different. Arcobacter sp., beta proteobacterium and Thiothrix sp. were the dominant species in all reactors, and played important roles in the reactor's operation.