Abstracto

Quantitative analysis of the composition and abundance of nitrifying bacteria in simultaneous nitrification and denitrification in SBBR

Hongwei Rong, Jingyin Wang, Chaosheng Zhang and Guanhua Gao

To reveal the effect of dissolved oxygen (DO) on the community structure of microorganisms during simultaneous nitrification and denitrification (SND) in the sequencing batch biofilm reactor (SBBR), the molecular biology techniques of denaturing gradient gel electrophoresis (DGGE), cloning and real-time PCR were applied. DGGE sequence analysis showed that some kinds of populations had been highly preponderant consistently, and cloning and phylogenetic tree of AOB gene revealed that Nitrsospira was the dominant species. Real-time PCR analysis indicated that the amount of AOB and NOB had the largest copy number on the bottom surface, and the population quantity ratio of AOB and NOB among three samples was "bottom surface �upper surface �inner layer". The result showed that DO concentration directly affected the proportion of aerobic fraction and anoxia fraction in the biofilm, which led to an effect on the efficiency of SND.