Environmental Biotechnology Lab, Department of Civil Engineering, The University of Hong Kong, Hong Kong, SAR, People's Republic of China.
Appl Microbiol Biotechnol. 2010 Dec;88(6):1403-12. doi: 10.1007/s00253-010-2837-3. Epub 2010 Aug 25.
The bacterial community in a partial nitrification reactor was analyzed on the basis of 16S rRNA gene by cloning-sequencing method, and the percentages of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the activated sludge were quantified by three independent methods, namely, denaturing gradient gel electrophoresis (DGGE), terminal restriction fragment length polymorphism (T-RFLP) and Double Monod modeling. The clone library results suggested that there were only a dominant AOB and a dominant NOB species in the reactor, belonging to Nitrosomonas genus and Nitrospira genus, respectively. The percentages of NOB in total bacterial community increased from almost 0% to 30% when dissolved oxygen (DO) levels were changed from 0.15 mg/L to 0.5 mg/L, coinciding with the accumulation and conversion of nitrite, while the percentages of AOB changed little in the two phases. The results confirmed the importance of low DO level for inhibiting NOB to achieve partial nitrification. Furthermore, the percentages of AOB and NOB in the total bacteria community were estimated based on the results of batch experiments using Double Monod model, and the results were comparable with those determined according to profiles of DGGE and T-RFLP.
采用克隆-测序法基于 16S rRNA 基因分析了部分硝化反应器中的细菌群落，并采用变性梯度凝胶电泳（DGGE）、末端限制性片段长度多态性（T-RFLP）和双 Monod 模型 3 种独立方法定量测定了活性污泥中氨氧化菌（AOB）和亚硝酸盐氧化菌（NOB）的比例。克隆文库结果表明，反应器中仅存在 1 种优势 AOB 和 1 种优势 NOB，分别属于亚硝化单胞菌属和硝化螺旋菌属。当溶解氧（DO）水平从 0.15mg/L 升高至 0.5mg/L 时，NOB 在总细菌群落中的比例从几乎 0%增加到 30%，与亚硝酸盐的积累和转化相吻合，而 AOB 的比例在这两个阶段变化不大。结果证实了低 DO 水平对抑制 NOB 以实现部分硝化的重要性。此外，根据双 Monod 模型的批实验结果估算了总细菌群落中 AOB 和 NOB 的比例，结果与根据 DGGE 和 T-RFLP 图谱确定的结果相当。
