有机碳源条件下厌氧氨氧化SBBR中的微生物多样性

研究有机碳源对SBBR厌氧氨氧化菌群等微生物的影响。采用16S rDNA序列与PCR-DGGE分析技术相结合的方法,对稳定运行的反应器内的活性污泥和生物膜样品,进行细菌多样性图谱分析,同时采用巢式PCR-DGGE技术对浮霉状菌属(Planctomycetes)细菌进行分析。结果表明,在有机碳源反应系统细菌条带数和多样性指数均高于无机系统,与活性污泥相比,生物膜表尤为明显。当进水不含有机碳源时,氨氧化细菌(ammonia oxidizing bacteria,AOB),厌氧氨氧化菌(anaerobic ammonia oxidizing bacteria,ANAMMOX)为优势功能菌;当进水含有机碳源时,系统中存在的AOB以亚硝化单胞菌(Nitrosomonas sp.)为优势菌群,同时存在反硝化菌,如索氏菌(Thauera sp.)以及厌氧氨氧化菌,它们共同作用完成N的去除。此外,与无机碳源系统相比,有机碳源的存在,有利于浮霉状菌的积累,但压缩了ANAMMOX的生存空间。本研究可为厌氧氨氧化工艺处理低C/N比有机废水提供了理论依据。

Microbial diversity in anaerobic ammonium oxidation reactor under organic carbon condition

In order to investigate the effects of organic carbon on microbial community, total bacterial genomic DNA was extracted from biomass in two SBBRs fed with inorganic and organic wastewater respectively. The molecular techniques based on the sequence of 16S rDNA V3 region gene and denaturing gradient gel electrophoresis (DGGE) were used to analyze the microbial community structures. Further, the Planctomycetes diversity was studied by nest PCR-DGGE. DGGE profiles show that the number of bands and the microbial diversity index of activated sludge and biofilm in reactor fed with organic wastewater, were higher than that of the reactor fed with inorganic wastewater. The profiles of Planctomycetes community in the two reactors are similar. The Nitrosomonas sp. (aerobic nitrifying bacteria), Candidatus Brocadia sp and uncultured anaerobic ammonium-oxidizing bacterium (the ANAMMOX bacteria) dominated in the reactor fed with inorganic wastewater. However, the numbers of ANAMMOX bacteria decreased and the denitrifying bacteria, such as Thauera sp, was found in the reactor fed with organic wastewater. The results revealed that the organic carbon helped to the accumulation of Planctomycetes, but the denitrifying bacteria could compete with ANAMMOX bacteria for living space. In conclusion, aerobic nitrifying bacteria, denitrifying bacteria and ANAMMOX bacteria could coexist and cooperate for nitrogen removal at C/N ratio of 1.2, which may have implications in the treatment of lower C/N organic wastewater.