厌氧氨氧化菌富集培养过程微生物群落结构及多样性

Microbial Community Structure and Diversity During the Enrichment of Anaerobic Ammonium Oxidation Bacteria

为深入理解厌氧氨氧化菌富集培养过程微生物群落变化特征,采用ASBR反应器进行厌氧氨氧化菌富集培养,考察了不同培养时间微生物群落组成、多样性及物种网络关系.结果表明,通过逐步提高基质浓度,实现了厌氧氨氧化菌富集,NH4+-N和NO2--N去除率分别为97.6%和95.4%,总氮去除率为84.9%.高通量测序发现,整个培养过程优势菌门(相对丰度>5%)为变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、绿弯菌门(Chloroflexi)、浮霉菌门(Planctomycetes)、装甲菌门(Armatimonadetes)和放线菌门(Actinobacteria);富集培养获得的主要厌氧氨氧化菌为Candidatus Brocadia,相对丰度从1.42%增长到24.66%;培养过程,微生物群落优势菌群组成未发生变化,但相对丰度呈现显著差异(P<0.05).富集培养过程不同时间,微生物群落α多样性呈现先升高后降低的趋势,且存在显著差异(P<0.05);微生物群落β多样性在富集培养过程发生明显空间分异特征,且存在显著差异(R=0.5672,P<0.01).培养过程不同时间,物种网络密度分别为0.188、0.068、0.059、0.18和0.0735;虽然富集培养过程导致微生物间的关联作用变弱,但浮霉菌门相关类群的物种成为网络中的主要节点.

To understand the changes in microbial community characteristics during the enrichment of anaerobic ammonium oxidation(ANAMMOX)bacteria,an ASBR reactor was used to culture the ANAMMOX bacteria.The composition,diversity,and species cooccurrence network of the microbial community were investigated under different cultivation times.The results showed that the ANAMMOX bacteria were enriched by gradually increasing the substrate concentration,with removal efficiencies for NH4+-N,NO2--N,and total nitrogen of 97.6%,95.4%,and 84.9%,respectively.The high-throughput sequencing found that the dominant phyla(relative abundance>5%)were Proteobacteria,Bacteroidetes,Chloroflexi,Planctomycetes,Armatimonadetes,and Actinobacteria in the whole culture process.Candidatus Brocadia was the main ANAMMOX bacteria in the reactor,with its relative abundance increasing from 1.42%to 24.66%.During the cultivation process,the composition of the dominant microbial community did not change,while the relative abundance showed a significant difference(P<0.05).The alpha diversity of the microbial community significantly increased first and then decreased(P<0.05),and the beta diversity of the microbial community was significantly spatially differentiated(R=0.5672,P<0.01)during the culture process.Species network densities were 0.188,0.068,0.059,0.18,and 0.0735 at different times during the culture process.Although the enrichment culture process resulted in weaker correlations between microorganisms,the related group of microorganisms in the phylum Aspergillus became the main node in the network.The enrichment process weakened the correlation between microorganisms;however,the microbial taxa related to the phylum Planctomycetes became the key node in the network.