基于细菌群体感应信号分子传递抑制的MBR膜污染控制技术及机制研究

At present, membrane biofouling is the main bottleneck of membrane bioreactor (MBR) development. Through the further analysis of bacterial quorum sensing (QS) system, this study found the inhibition of the bacterial multidrug efflux pump inhibit the transport of signal molecules from intracellular to extracellular, and then reduce the accumulation of signal molecules in environment. The applicant first propose MBR membrane biofouling control strategy based on the inhibition of QS signals transport. In order to rightly analyze the inhibitory mechanism of STI on MBR membrane biofouling, this study select bacteria with typical QS systems as target bacteria and apply the metabolic uncoupler and plant extract which inhibit the function of bacterial efflux pump as QS signal transport inhibitor (STI) to reveal the inhibitory effect of STI on single target bacterial biofilm and the QS regulation mechanism. This study build the MBR membrane biofouling control technology based on the inhibition of bacterial quorum sensing signals transport to study the inhibitory effect of STIs on biofouling. Through the analysis of microbial community, QS signals and function genes, this study will illuminate the MBR biofouling inhibitory mechanism and mixed bacterial biofilm QS regulation mechanism of STI. At the same time, this study analyze the effect of efflux pump inhibition on horizontal transfer of antibiotic resistance genes. These results of this study will provide theoretical and technical supports to establish a safe and efficient technology for membrane biofouling control in MBR.

目前，膜污染问题是制约MBR工艺发展的主要瓶颈。本研究通过对细菌群体感应系统的深入分析，发现抑制细菌药物外排泵功能可以抑制信号分子从胞内向胞外的传递，减少环境介质中信号分子的积累，首次提出基于细菌群体感应信号分子传递抑制的膜污染控制策略。为探究信号分子传递抑制的膜污染控制机制，选取具备典型群体感应系统的目标细菌，利用抑制细菌药物外排泵功能的代谢解偶联剂和植物提取物作为信号分子传递抑制剂，揭示信号分子传递抑制对单一目标细菌生物膜的抑制效果和群体感应调控机制；构建基于细菌群体感应信号分子传递抑制的膜污染控制技术，研究多种信号分子传递抑制剂的膜污染控制效果，通过微生物群落分析、信号分子检测和功能基因分析阐明基于信号分子传递抑制的MBR膜污染控制机制和混菌生物膜群体感应调控机制；同时，解析抑制细菌药物外排泵对抗性基因水平转移的潜在影响。研究成果为建立安全高效的膜污染控制技术提供理论依据和数据支撑。

调控细菌群体感应（QS）已被广泛用于控制生物膜的形成和膜生物反应器（MBR）中的生物污染。本研究以控制MBR中生物污染为目标，采用两种调控途径：信号分子传递抑制剂（解偶联剂TCS、植物提取物黄芪甲苷、丁香酚和黄芩素）和群体猝灭菌（QQ菌，皮特不动杆菌HITSZ001）实现对细菌生物膜形成的调控，完成了抑制剂及QQ菌对目标革兰氏阴性菌和革兰氏阳性菌生物膜的抑制效果的研究。通过测定目标细菌信号分子分泌、EPS分泌及与QS和生物膜形成相关基因的变化情况，确定了各信号分子传递抑制剂对目标细菌生物膜形成的抑制机制；通过测定QQ菌分泌的信号分子降解酶、鉴定其功能基因及分析目标菌QS相关基因的变化情况，揭示了QQ菌对目标细菌生物膜形成的调控机制。在应用方面，分别将信号分子传递抑制剂（TCS和黄芪甲苷）及QQ菌（海藻酸钠固定）投加至实验室小试规模MBR系统中，构建了三种不同的膜污染控制技术，探明了三种调控技术对MBR中膜污染的控制效果并解析了MBR中EPS、信号分子及污泥群落结构的变化，进一步揭示了群体感应对膜污染的控制机制，为膜污染控制策略提供了技术支持和理论支撑。