T-RFLP方法分析城市污水处理厂中细菌群落的动态变化

采用基于16SrRNA基因的末端限制性片段长度多态性技术(T-RFLP),分析了功能稳定的2个城市污水处理系统中(系统A及系统B),细菌群落结构在105d中的动态变化.在研究中,系统A和系统B功能稳定,BOD出水浓度均在8mg/L左右,总氮(TN)出水浓度分别在25mg/L和23mg/L之下.T-RFLP图谱分析表明,系统A中,115、118、123、471、482和835bp等T-RFs的相对丰度变化显著,系统B中,123、471、750和835bp等T-RFs的相对丰度变化显著.移动窗口分析表明,系统A中细菌群落的平均变化率Δt(15d)为21.5%±5.7%,系统B的平均变化率Δt(15d)为22.6%±5.0%.洛伦兹曲线分析表明,系统A中20%的微生物的累积相对丰度为43%～50%;系统B中20%的微生物的累积相对丰度为47%～52%.结果表明,在城市污水处理厂中,稳定的功能并没有藕联着稳定的细菌群落结构.

Bacterial Community Dynamics in Wastewater Treatment Plants Based on T-RFLP Profiles

Bacterial communities in two full-scale wastewater treatment systems (system A and system B) with functional stability were monitored over 105 days using terminal restriction fragment length polymorphism (T-RFLP) based on 16S rRNA genes. During the study period, system A and system B were functionally stable. The effluent BOD concentration of two systems was always around 8 mg/L, and at the same time the effluent TN concentrations of two systems were always below 25 mg/L and 23 mg/L respectively. However, the T-RFLP profiles showed that for system A, the relative abundance of T-RF of 115, 118, 123, 471, 482 and 835 bp changed significantly. For system B, the T-RF of 123, 471, 750 and 835 bp changed significantly. The moving window analysis showed the average community change rates (every 15 days) of system A and system B were 21.5%±5.7% and 22.6%±5.0% respectively.Based on the Lorenz curves, it was observed for system A that 20% of the species corresponded with 43% to 50% of the cumulative relative abundance. For system B, 20% of the species corresponded with 47% to 52% of the cumulative relative abundance. In conclusion, the results of this study clearly revealed that, in the full-scale wastewater treatment systems, the functional stability did not correlate to the stable bacterial communities.