处理不同废水MBR系统中微生物群落结构的比较

Comparison of Microbial Community Structure in MBRs Treating Different Wastewater

为了研究膜生物反应器中微生物群落结构与系统处理效能的关系,为工艺改进提供依据,从4种处理不同水质的MBR污泥中提取细菌总基因组DNA,采用PCR-DGGE和克隆测序技术对系统中的微生物群落结构进行了解析,根据序列数据进行同源性分析并建立了系统发育树.结果表明,在长期稳定运行后不同MBR中形成了各自特有的生态群落,进水水质对总细菌的群落结构有着较大的影响,处理含有较复杂成分废水的反应器中,种群多样性较高,Shannon指数分别为0.77和0.78.总细菌中,主要优势种群以Proteobacteria纲(8个OUTs)和Bacillus属(2个OUTs)为主.不同反应器中氨氧化菌群结构较为相似,存在着相同的顶级优势群落;测序结果表明MBR中存在着多种亚硝化菌属,其中以亚硝化单胞菌属最为普遍,并鉴定出2株反硝化菌属Uncultured Achromobacter sp.和Unculture ddenitrifying bacterium,说明反应器中可能同时存在多种硝化和脱氮途径.

In order to investigate the microbial community structures in different membrane bioreactors, total bacterial genomic DNA was extracted from biomass in four MBRs treating different wastewater. The microbial community structures were studied by polymerase chain reaction-denaturing gradient gel electrophoresis（PCR-DGGE） and cloning-sequencing. Furthermore, and the sequences were used for homology analysis and then two phylogenetic trees were constructed. Results indicate that each MBR owns its specific ecological community after a longterm of operation. Influent wastewater composition has a significant impact on total bacterial community structures. Population diversity, which is in the bioreactor fed with more complex components wastewater, is higher than those of other MBRs. The Shannop Index are 0.77 and 0.78. Proteobacteria and Bacillus, which contain 8 OUTs and 2 OUTs, are the climax communities in the investigable MBRs, The profiles of ammonia-oxidizing bacterial community in the four reactors are very similar. There may exist several modes of nitrification and denitrification in MBR because sequences revealed that there exist multitude nitrifying organisms, in which Nitrosomonas are the most predominant, and two denitrifying bacterium （uncultured Achromobacter sp. and uncultured denitrifying bacterium）in reactors.