同步脱氮除磷好氧颗粒污泥培养过程微生物群落变化

Microbial Population Dynamics During Sludge Granulation in a Simultaneous Nitrogen and Phosphorus Removal System

本实验利用生活污水培养具有同步脱氮除磷(simultaneous nitrogen and phosphorus removal,SNPR)功能的好氧颗粒污泥(aerobic granular sludge,AGS).采用Illumina Mi Seq PE300高通量测序对AGS培养过程中细菌群落变化进行了研究,以期揭示污泥好氧颗粒化成因.采用实时荧光定量PCR对AGS培养过程中氨氧化细菌(ammonia-oxidizing bacteria,AOB)、氨氧化古菌(ammonia-oxidizing archaea,AOA)、亚硝酸盐氧化菌(nitrite-oxidizing bacteria,NOB)和聚磷菌(polyphosphate accumulating organisms,PAOs)的丰度变化进行了研究.结果表明:历时100 d培养出的AGS质地紧实,具有良好的SNPR效果.AGS胞外聚合物(extracellular polymeric substances,EPS)中多糖含量在培养过程中增加明显,而蛋白质含量保持稳定.AGS培养过程中,AOB的丰度略微下降,AOA的丰度明显下降,NOB的丰度无明显变化,而PAOs的丰度在AGS培养初期明显增加.在AGS培养过程中,细菌群落多样性呈现出先升高后降低的趋势,且细菌群落组成发生了明显的变化.持久型OTUs占样品总序列数的92.70%,其中变形菌门(Proteobacteria,31.07%~53.67%)、拟杆菌门(Bacteroidetes,6.70%~16.50%)和绿弯菌门(Chloroflexi,7.84%~13.36%)是AGS培养过程中的细菌优势门.Candidatus competibacter属在AGS培养过程中大量富集(由种泥中的0.11%增加到35.33%),其可能会分泌胞外多糖,形成黏性EPS,促进絮状污泥团聚成为AGS.

In this study,domestic sewage was utilized to cultivate aerobic granular sludge（AGS） in a simultaneous nitrogen and phosphorus removal（SNPR） system.The bacterial population dynamics during the aerobic sludge granulation were investigated to reveal the granulation mechanisms using Illumina Mi Seq PE300 high-throughput sequencing.Quantitative real time polymerase chain reactions（PCR） were used to investigate shifts in the abundance of ammonia-oxidizing bacteria（AOB）,ammonia-oxidizing archaea（AOA）,nitrite-oxidizing bacteria（NOB） and polyphosphate accumulating organisms（PAOs）.After cultivation for 100 d,the AGS was compact and demonstrated good SNPR performance.During the AGS formation process,extracellular polysaccharides obviously increased,while extracellular proteins kept relatively stable.The abundance of AOA significantly decreased during the formation of AGS process,while the abundance of PAOs increased.The bacterial diversity increased at first and then decreased during the formation of AGS.The bacterial community changed dramatically during aerobic sludge granulation.Persistent operational taxonomic units（OTUs） accounted for 92.70% of the total sequences.Proteobacteria（31.07%-53.67%）,Bacteroidetes（6.70%-16.50%） and Chloroflexi（7.84%-13.36%） were the dominant phyla.Candidatus competibacter was obviously enriched in the AGS formation process（increased from 0.11% in the seed sludge to 35.33% in the AGS） and may play an important role in the formation of AGS.