基于宏基因组的城市污水处理厂生物脱氮污泥菌群结构分析

Unraveling Microbial Structure of Activated Sludge in a Full-scale Nitrogen Removal Plant Using Metagenomic Sequencing

为了探求活性污泥系统中含有的复杂微生物群落对污水处理厂污水中污染物去除的重要作用,通过对Illumina Hi Seq 4000平台宏基因组测序结果分析,探究了污水处理厂中生物脱氮系统中的微生物群落的多样性、功能菌种以及主要的代谢途径.在KEEG和COG数据库水平上进行生物分类和功能注释.生物检测结果表明:在门水平上的优势菌种是:变形菌门、拟杆菌门、硝化螺旋菌门、放线菌门、绿弯菌门、厚壁菌门.各个菌的丰度分别占到测序细菌的53. 6%、25. 3%、5. 86%、2. 43%、1. 71%、1. 46%. Nitrosomonas、Nitrospira和Thauera菌是检测到的典型的AOB、NOB和反硝化菌,分别占到5. 82%、2. 26%、4. 30%,表明该生物系统具有良好的脱氮性能.同时,对氮循环过程中的各种主要的酶进行了阐述,量化分析了硝化和反硝化过程中涉及的功能基因(amo:1 966 hits,hao:1 000hits,nar G:8 204 hits,nap A:1 828 hits,nirk:1 854 hits,nor B:2 538 hits,nos Z:5 158 hits),同时亚硝酸盐氧化还原酶的功能基因数量为8 204 hits.本研究对生物脱氮系统中的菌群结构和多样性做了综合的阐述,可为优化系统中营养物的去除提供理论基础.

To investigate the vital role of complex microbial communities in activated sludge about the pollutant removal in wastewater treatment plants (WWTPs), metagenomic sequencing on Illumina HiSeq 4000 platform was applied to characterize microbial community, functional profiles and metabolic pathway within activated sludge from a full-scale municipal WWTP. The microbial community was conducted taxonomic and function annotations based on KEEG and COG database. Taxonomic analysis show that the dominant bacterial phyla are Proteobacteria, Bacteroidetes, Nitrospirae, Actinobacteria Chloroflexi and Firmicutes(the abundance are 53.6%, 25.3%, 5.86%, 2.43%, 1.71%, and 1.46%, respectively, of the overall population reads). The key organisms involve Nitrosomonas, Nitrospira and Thauera (approximately 5.82%, 2.26% and 4.30%, respectively), which are the typical ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB) bacteria and denitrifying bacteria. These functional microorganisms carry out biological nitrogen removal (BNR). Various key enzymes involved in the global nitrogen cycle are annotated in the activated sludge. The abundance of the functional genes in the BNR is quantified (amo:1 966 hits, hao:1000 hits, narG:8204 hits, napA:1 828 hits, nirk:1 854 hits, norB: 2538 hits, and nosZ:5 158 hits). The function genic abundance of nitrite oxidordeuctase is 8248 hits. This study provides a comprehensive insight into the community structure and diversity of the BNR system, and will provide foundation for optimal operation of nutrient removal systems.