硝化型生物絮团的驯化培养

Domestication and cultivation of nitrifying bio-floc

为培养硝化型生物絮团、减少碳源投加、提高絮团效率并缩短培养周期,文章采用养殖废水排污口底泥为接种污泥培养生物絮团,通过逐渐减少碳源投加,开展了硝化型生物絮团的定向培养,并结合高通量测序分析了生物絮团菌群变化。结果显示,排污口底泥主要优势菌群与其他报道的异养生物絮团一致,具有良好的微生物菌群基础,能够在7 d 内形成出水稳定的生物絮团。随着碳源减少,生物絮团微生物菌群结构随之改变,32 d后形成硝化型生物絮团。高通量测序结果显示,接种污泥和硝化型生物絮团主要优势菌群均为变形菌门和拟杆菌门。在纲水平上,原始污泥优势菌群为Gammaproteobacteria (γ-变形杆菌属)、Bacteroidia (拟杆菌属)和Deltaproteobacteria (δ-变形杆菌属),而硝化型生物絮团优势菌群为Bacteroidia、Gammaproteobacteria 和Anaerolineae(厌氧绳菌属)。硝化型生物絮团硝化菌总相对丰度对比原始污泥有了较大提高,出水水质稳定,能有效调控养殖后期水质并降低养殖成本。

In this study, nitrifying biofloc was cultivated from sewage outlet sediment by gradually reducing carbon source so as to improve its nitrogen removal performance, reduce the cost and shorten the culture period. High throughput sequencing technology was used to analyze the bacterial community structure of the seed sludge and nitrifying biofloc. The results show that the main dominant flora of seed sludge was consistent with other reported heterotrophic flocs, indicating that the sewage outlet sediment has good microbial flora foundation and can form nitrogen removal stable biofloc within 7 d. As the decrease of carbon source, the microbial flora structure of heterotrophic biofloc changed, and the nitrifying biofloc gradually formed after 32-day target training. The dominant bacterial communities of the seed sludge and nitrifying biofloc were Proteobacteria and Bacteroidetes. At Class level, the dominant flora of seed sludge were Gammaproteobacteria, Bacteroidia and Deltaproteobacteria, while the dominant flora of nitrifying biofloc were Bacteroidia, Gammaproteobacteria and Anerolineae. Among them, the total relative abundance of nitrifying bacteria in nitrifying biofloc had greatly increased compared with the seed sludge. The nitrifying biofloc contributes to high nitrogen removal performance and less aquaculture cost.