污泥好氧颗粒化过程中氨氧化菌群结构的演替与分析

Evolution and analysis of ammonia-oxidizing bacteria communities during aerobic sludge granulation

为了揭示颗粒污泥形成过程中氨氧化菌(AOB)群落结构的演替规律,利用变性梯度凝胶电泳(DGGE)、克隆测序和实时定量聚合酶链式反应(real-time PCR)等分子生物学技术对AOB群落的演替进行了研究。DGGE结果表明,污泥接种驯化期,AOB群结构的变化较为剧烈,在外加选择压的作用下,种群多样性迅速下降;但随着污泥颗粒化的完成而趋于稳定。测序结果表明,接种污泥中的大多数亚硝化单胞菌属因可快速适应工艺的淘洗过程而被保留在系统内,而亚硝化螺菌属逐渐被淘汰。real-time PCR结果表明,在经历了运行初期的淘洗后,AOB含量随着污泥浓度的提高而逐渐增长;但污泥的氨氧化活性随着污泥浓度的增长而降低。

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.