微氧折流反应器中产甲烷菌的分布与群落结构分析

Distribution and community structures of methanogens in a microaerobic baffled reactor

为了研究微氧条件下折流反应器处理生活污水的微生物学机理,针对产甲烷菌的MCR基因采用实时荧光定量PCR和构建克隆文库的方法,对反应器中的关键功能微生物产甲烷菌的分布特点与群落结构变化进行了分析。结果表明,微氧条件下折流反应器的环境条件可以保证产甲烷菌的增长,不同格室的产甲烷菌丰度均要高于接种污泥(1 720 copies/ng),其中经过微氧曝气处理的1#(2 864 copies/ng)和2#(2 282 copies/ng)格室产甲烷菌丰度低于厌氧状态的3#(3 508copies/ng)格室;微氧处理后折流反应器产甲烷菌的群落结构发生了明显的变化,接种污泥的产甲烷菌多属于Methanomicrobiales目的 Methanoregulaceae属(6/9),而保持微氧状态的1#格室中产甲烷菌多隶属于Methanomicrobiales目(6/10)的其他类群,2#格室的产甲烷菌则多隶属于Methanobacteriales目(5/10),保持厌氧状态的3#格室的产甲烷菌主要属于Methanomicrobiales目(3/10)和Methanosarcinales目(3/10);产甲烷菌MCR基因的多样性指数表明微氧曝气的引入降低了活性污泥中产甲烷菌的生物多样性。

In order to study the microbial mechanism of the baffled reactor treating domestic wastewater under microaerobic condition,the distribution and the community structure of methanogen which is the key functional microorganism in the reactor were analyzed by real-time quantitative PCR and clone library. The results showed that the environmental conditions of the baffled reactor under microaerobic operation would ensure the growth of methanogens. The abundance of methanogens in different cells were higher than those in the inoculation sludge( 1 720 copies /ng). The abundance of methanogens of the cell 1#( 2 864 copies/ng) and 2#( 2 282 copies /ng) which were treated by micro-oxygen aeration were lower than that of the cell 3#( 3 508 copies/ng) in the anaerobic state. There was a significant change of the community structure of methanogens in the baffled reactor under micoaerobic condition. The most of methanogens of the inoculation sludge fell into the family of Methanoregulaceae( 6 /9) associated with the order of Methanomicrobiales,while the methanogens of the cell 1#were mostly affiliated with the other families within the order of Methanomicrobiales( 6 /10). The methanogens of the cell 2#were mostly affiliated with the order of Methanobacteriales( 5 /10),and the methanogens of the cell 3#maintained in anaerobic state mainly belonged to the order of Methanomicrobiales( 3 /10) and Methanosarcinales( 3/10). The diversity indices based on the sequences of MCR gene showed that the introducing of micro-oxygen aeration reduced the biodiversity of methanogen in the activated sludge.