基于好氧甲烷氧化菌的反硝化效能及微生物群落研究

Denitrification efficiency and microbial community research in an aerobic methanotroph-based system

采用气体循环序批式生物膜反应器(gcSBBR),构建反硝化型甲烷好氧氧化(AME-D)系统.考察了进水氮负荷的影响,发现氮负荷为0.075kg/(m3·d)时,硝酸盐氮去除率达到98.93%,其反硝化速率为74.25mg/(L·d),系统的甲烷日平均消耗量为35.91%(初期为50%);扫描电子显微镜(SEM)分析结果显示,系统中的微生物主要以短杆菌(12~18μm)为主,并存在少量的丝状菌(长150~200μm);16S rRNA高通量测序结果显示,该系统中的甲烷氧化菌为Methylocaldum、Methylomonas、Methylococcus和Methylococcaceae_unclassified,反硝化菌为Denitratisoma、Hydrogenophaga、Azoarcus、Thiobacillus和Rhodobacter,其中主要的功能微生物为Methylocaldum、Denitratisoma和Hydrogenophaga,系统对氮的去除是由好氧甲烷氧化菌与反硝化菌协同实现.此外,系统中存在大量以甲醇和甲基胺类物质为生长基质的Methylophilaceae_uncultured(30.4%).

An aerobic methane oxidation coupled to denitrification(AME-D)was constructed using a gas circulation sequencing batch biofilm reactor(gcSBBR),and nitrogen loading in influent was observed.It was found that the removal rate of nitrate nitrogen reached 98.93%and the denitrification rate 74.25mg/(L·d)when the nitrogen load was 0.075kg/(m3·d),and the average daily consumption of methane was 35.91%(at the initial stage:50%).According to scanning electron microscopy(SEM)results,microorganisms in the system were mainly Bacillus brevis(12~18μm),dotted with a few filamentous bacteria(150~200μm).The high-throughput sequencing of 16S rRNA indicated that methanotroph were Methylocaldum,Methylomonas,Methylococcus and Methylococcaceae_unclassified,the denitrifying bacteria Denittrasoma,Hydrogenophaga,Azoarcus,Thiobacillus and Rhodobacter,and the main functional bacteria Methylocaldum,Denittrasoma and Hydrogenophaga in this system.Nitrogen was removed by the synergism of aerobic methanotroph and denitrifying bacteria.In addition,a large volume of Methylophilaceae_uncultured(30.4%),which utilized methanol and methylamine as growth substrates,was found.