Microbial diversity in anaerobic ammonium oxidation reactor under organic carbon condition
有机碳源条件下厌氧氨氧化SBBR中的微生物多样性

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.