Abstract:  In order to explore the effect of biofilm culturing methods on start-up time of fluidized-sand biofilter (FSB) and structure of microbial community, understand the water purification mechanism of FSB, and apply it to Chinese sturgeon recirculating aquaculture system, the start-up time of FSB when using natural biofilm culturing method and inoculating probiotics was studied, and the change of structure of the microbial community in FSB at different times was analyzed with pyrosequencing method. The results showed that the start-up time of FSB when inoculating probiotics was significantly shorter than that when using natural biofilm culturing method. At the early period of biofilm culturing, the microbial species on the surface of filter material carrier was few, and the predominant bacteria were firmicutes. After the biofilm got mature, the diversity of bacterial community in the biofilter when using natural biofilm culturing method was significantly higher than that when inoculating probiotics, the community structure was more stable, and the proportion of functional bacteria was also higher than that of the inoculation method, such as Flavobacterium and purple nonsulfur bacteria, which indicated that the natural biofilm culturing method was more conducive to the stable operation of FSB.

Key words: Fluidized-sand biofilter, biofilm culturing methods, structure of bacterial community, pyrosequencing, Chinese sturgeon

摘要： 为探讨挂膜方式对流化床生物滤器的启动时间及其对微生物群落结构的影响，了解流化床生物滤器的净水机制，并将其应用于中华鲟循环水养殖系统中，研究自然挂膜法和接种微生态制剂2种挂膜法工况下滤器的启动时间，并采用焦磷酸测序方法，分析不同时期滤器中微生物群落结构的变化。结果显示：采用接种微生态制剂挂膜法滤器启动的时间显著短于采用自然挂膜法。挂膜初期，两种挂膜方式下滤料载体表面微生物种类较少，其优势细菌都是厚壁菌门；生物膜成熟后，采用自然挂膜法的滤器中细菌群落的多样性显著高于采用接种微生态制剂培养法，并且群落结构更加稳定，筛选出的功能性细菌的比例也高于采用接种挂膜方式，如黄杆菌属（Flavobacterium）和紫色非硫细菌( purple nonsulfur bacteria)等，表明采用自然挂膜法更利于流化床生物滤器的稳定运行。

关键词: 流化床生物滤器, 挂膜方式, 细菌群落结构, 焦磷酸测序, 中华鲟