膜生物污染中群体感应机理与抗污染超滤/反渗透膜改性研究

Membrane biofouling is a critical challenge in the water treatment applications of membrane separation technology. The regulation of biofilm formation by quorum sensing has been widely proved. Quorum quenching will be a very promising approach in biofouling control. However, biofouling control via quorum quenching is not yet well-studied. The objective of this project is to systematically study the quorum-sensing-mediated membrane biofouling control. Our previous research on membrane fouling and microorganism had shed light on the fundamentals of this project. The biofilm formation and bacteria diversity on fouled membrane will be investigated. Autoinducers synthesised and released by biofilm bacteria will be characterized, and thereby identify the quorum sensing mechanism biofilm formation, and the strategies of quorum quenching. The characteristics and identification of quorum quenching bacteria from biofilm will be explored. Quorum sensing inhibiting material will be screened and their interference in bacteria proliferation and biofilm formation will be elucidated. The approaches to incorporate quorum quenching into membrane modification will be developed, and then the activity and stability will be evaluated. A series of quorum sensing inhibitor and modification methods will be studied. Their effects on membrane separation property optimization and antibiofouling enhancement will be assessed. The studies in this project will provide novel theory and technology for the development of innovative antibiofouling membrane for advanced water treatment.

生物污染是膜法水处理应用面临的主要问题之一。细菌群体感应对生物膜形成的调控作用已被广泛验证，利用群体淬灭抑制生物污染是一项很有潜力的新技术，但在水处理膜生物污染中尚未深入研究。本项目在前期膜污染及生物膜研究的基础上，提出了基于群体感应理论的抗生物污染膜改性研究，分析膜表面及微孔内生物膜形成机理及细菌群落结构，检测分析生物膜内细菌合成释放的信号分子，系统研究生物膜基因表达的群体感应调控机制与群体淬灭途径。阐明膜过滤系统群体淬灭菌生理特性及识别。探讨生物提取与人工合成群体感应抑制剂对细菌增殖和生物膜形成的干扰机理。基于群体感应抑制探索膜抗生物污染性能优化的方法，评价改性膜群体淬灭活性和稳定性。分析不同群体感应抑制剂和改性方法对膜物理化学特性、分离性能、抗污染性能的影响。本研究将为研发新型抗生物污染水处理膜提供新思路。

膜生物污染控制是水处理膜分离技术领域的研究重点。细菌可产生和检测特定自诱导物分子从而调控生物膜形成等群体行为，通过干扰群体感应通路抑制生物污染是膜技术领域新兴的研究课题。本项目基于群体感应理论研究了有机膜的抗生物污染改性。采用4-羟基-3-甲氧基苯甲醛等群体感应抑制剂对超滤膜和反渗透膜进行改性，制备的改性选择层具有良好的亲水性和稳定性。采用N-酰基氨基酸酰胺水解酶通过表面涂覆和化学交联对超滤膜和反渗透膜进行改性，提高细菌群体感应抑制的作用范围。分析了抑制剂和改性方法对膜物理化学特性和分离性能的影响。改性超滤膜和反渗透膜表面细菌初始粘附减缓，阻碍了生物膜的形成。在此基础上结合生物处理工艺，采用生物接触氧化反应器处理出水为料液研究膜抗生物污染性能。通过向膜表面环境释放群体感应抑制剂，改性膜可有效控制膜表面的微生物集聚及维持较高的水通量。项目从污水处理厂活性污泥中定向分离出以酰基高丝氨酸内酯为碳源的群体淬灭菌。在膜过滤测试中，淬灭菌的引入使生物污染引起的水通量损失减少。采用宏基因组测序对进水和膜表面微生物多样性和细菌群落结构进行分析，研究生物膜的群体感应调控和淬灭机理。未改性膜表面形成的生物膜优势菌与进水菌群组成相似。经群体感应抑制剂改性后，膜表面肠杆菌和不动杆菌等细菌生长受到抑制，而嗜酸菌等细菌的相对丰度显著提高。群体淬灭菌由于可分泌多种淬灭酶，对菌群结构有复杂的影响。本项目的研究扩展了基于群体感应的水处理膜生物污染控制理论和方法，为新型抗污染膜材料的开发提供了新思路。