基于高通量测序的流化床生物滤器细菌群落结构分析

为了解流化床生物滤器内部细菌群落组成及其净水机制,通过高通量测序方法,研究了不同时期滤器中表层和底层滤料的细菌群落结构,分析了滤器不同床层的营养盐变化情况及水处理性能.结果表明,滤器的硝化作用主要发生于床层下部,表层对其的贡献率不显著.稳定工况下,流化床生物滤器对NH_4~+-N、TN、BOD_5和SS的去除率达到(68.3±2.24)%、(49.54±3.56)%、(60.35±4.98)%和(45.21±2.11)%,对氨氮的去除负荷达到(343.28±75.5)g·(m~3·d)~(-1),其硝化性能优于常规生物滤器.试验共筛选31个门,490个细菌属,其生物多样性显著高于常规生物滤器.自清洗装置的启停对滤器中不同区域载体表面细菌的多样性没有影响,对各样品的优势菌群略有影响.在滤器稳定运行时,表层区域的优势细菌基本维持不变,主要包括厌氧绳菌科、黄杆菌科、红杆菌科、硝化螺菌属、暖绳菌科.而底层区域的优势细菌随着时间的推移有所变化,主要包括硝化螺菌属、微丝菌属、Muricauda、Defluviimonas、红杆菌科.

Analysis of Microbial Diversity in a Fluidized-Sand Biofilter Based on High-Throughput Sequencing Technology

In order to understand the microbial community composition and mechanism of purifying aquaculture water with a biofilter that was been applied to spotted parrotfish recirculating aquaculture systems with microglass beads as the biofilter filler, the changes in the nutrients of different biological filter beds and the water treatment performance of a fluidized-sand biofilter were analyzed. By using high-throughput sequencing technology, the microbial community structure of the surface area and bottom area at different times were studied. The results show that the fluidized-sand biofilter successfully start-up after one month under marine culture. Nitrification of the biofilter occurred mainly in the lower bed layer; the surface area played a small role in eliminating the NH₄⁺-N. The average removal rates of NH₄⁺-N, TN, BOD₅, and SS were 68.3%±2.24%, 49.54%±3.56%, 60.35%±4.98%, and 45.21%±2.11%, respectively. The average NH₄⁺-N removal load reached (343.28±75.5) g·(m³·d)^-1, which showed a better performance of wastewater treatment. In this experiment, 31 phyla and 490 genera were identified, thus the biological diversity was significantly higher than that of the other conventional microbial biofilter. Start-stop cycling of the self-cleaning device in the biofilter had no effect on the microbial diversity of different regional, but had some effect on the dominant bacterial community of the microglass beads surface. Under opening self-cleaning device regularly condition, the microbial species of the surface and bottom areas became significantly similar. With time, the microbial species of the superficial area and bottom area had no significant change, and the microbial population structure was relatively stable. In the biofilm training period, the diversity of microbial communities was significantly lower than it was after biofilm maturation. At the time of biofilter stable operation, the dominant bacteria of the superficial zone essentially remained unchanged and mainly included Anaerolineaceae_uncultured (8.4%-28%), Flavobacteriaceae_unclassified (1.1%-32%), Rhodobacteraceae_uncultured (2.3%-17%), Nitrospira(1%-7%), and Caldilineaceae_uncultured (1%-6%). The dominant bacteria of the bottom zone changed over time and mainly include Nitrospira (12.45%-17.06%), Candidatus_Microthrix (2.6%-8.8%), Muricauda (4.8%-6.3%), Defluviimonas (6%-7%), and Rhodobacteraceae_uncultured (2%-6.2%). Among them, the abundance of Nitrospira was significantly higher than that in the other biofilter.