Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing, China; CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei, China.
CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei, China.
Water Res. 2017 Nov 15;125:309-317. doi: 10.1016/j.watres.2017.08.061. Epub 2017 Aug 29.
Quorum sensing (QS), especially acyl homoserine lactone (AHL)-mediated QS, in activated sludge arouses great interests because of its vital role in the formation of biofilm and aerobic granules (AG). Although QS is reported to be largely related to the properties of activated sludge, it is not economically feasible to tune QS in an activated sludge reactor through dosing pure AHL or AHL hydrolase. A more reasonable way to tune QS is to augment reactors with AHL-producing or -quenching bacteria. In this work, the impacts of continuous dose of AHL-producing or -quenching strains on the activated sludge during its granulation process were explored. Augmentation of AHL-producing or -quenching strains resulted in up- or down-regulation of the AHL concentration in the reactors. Granulation of activated sludge was also accomplished in all reactors, but the granules showed negligible or slight differences in the physicochemical properties of sludge, such as nutrients removal, biomass concentration, extracellular polymeric substances, and zeta potential. Interestingly, a smaller granule size was observed for both the reactor augmented with either an AHL-quenching strain or an AHL-producing strain, suggesting that the AHL augmentation suppressed the biofilm development. Pyrosequencing analysis reveals that the granules cultured in the reactors varied widely in bacterial community structure, indicating that the AHL augmentation had a greater impact on the bacterial community structure, rather than on the physicochemical properties of activated sludge. These results demonstrate that the role of QS in the biofilm formation in complex wastewater treatment bioreactors should be re-evaluated.
群体感应（QS），特别是酰基高丝氨酸内酯（AHL）介导的 QS，在活性污泥中引起了极大的兴趣，因为它在生物膜和好氧颗粒（AG）的形成中起着至关重要的作用。虽然 QS 被报道与活性污泥的性质有很大关系，但通过投加纯 AHL 或 AHL 水解酶来调节活性污泥中的 QS 在经济上是不可行的。更合理的调节 QS 的方法是通过添加产 AHL 或淬灭 AHL 的细菌来增强反应器。在这项工作中，探索了连续投加产 AHL 或淬灭 AHL 菌株对活性污泥在颗粒化过程中的影响。添加产 AHL 或淬灭 AHL 菌株会导致反应器中 AHL 浓度的上调或下调。所有反应器都完成了活性污泥的颗粒化，但颗粒在污泥的物理化学性质（如营养物去除、生物量浓度、胞外聚合物和 ζ 电位）方面几乎没有或只有轻微的差异。有趣的是，无论是添加 AHL 淬灭菌株还是 AHL 产生菌株的反应器，都观察到颗粒的粒径较小，这表明 AHL 的添加抑制了生物膜的发展。焦磷酸测序分析表明，在反应器中培养的颗粒在细菌群落结构上差异很大，这表明 AHL 的添加对细菌群落结构的影响大于对活性污泥物理化学性质的影响。这些结果表明，QS 在复杂废水处理生物反应器中生物膜形成中的作用需要重新评估。
