Evolution and analysis of ammonia-oxidizing bacteria communities during aerobic sludge granulation
污泥好氧颗粒化过程中氨氧化菌群结构的演替与分析

In order to reveal the succession procedure of ammonia-oxidizing bacteria(AOB) community diversity during sludge granulation, the molecular biological techniques denaturing gradient gel electrophoresis (DGGE), cloning-sequencing and real-time quantitative polymerase chain reaction (real-time PCR) were applied to study the succession of ammonia-oxidizing bacterial community. DGGE results showed that the variation of AOB was remarkable in the period of sludge inoculation, and the AOB diversity declined due to the selection pressure imposed by process conditions. Subsequently, AOB community structure tended to be stable along with granules formation. Sequencing results demonstrated that most of Nitrosomonas in the inoculating sludge were remained because of their ability to rapidly adapt to the settling-washing out action. However, all of Nitrosospira sp. was gradually eliminated. The results of real-time PCR indicated that the amount of AOB increased gradually after undergoing the early stage of wash-out. However, ammonia-oxidizing activity of biomass decreased along with the increase of MLSS.