基于生物刺激的群体感应调控及MBR膜污染控制研究

Membrane fouling is a critical bottleneck for membrane bioreactor (MBR) technology, which need to be addressed urgently. Quenching the microbial quorum sensing (QS), which incurs membrane biofouling, is a promising way to tackle the fouling problem in MBR. Currently, quorum quenching (QQ) bacteria screening coupled with functional bacteria immobilization were commonly used to suppress QS in MBR in published research. However, this approach is complex and the immobilization will restrain the nutrient acquisition and the degradation of signal molecules, and thus suppress QQ. In order to address the problem, it is proposed to promote the growth of autochthonous QQ bacteria in situ by dosing biostimulants (special carbon source), and accordingly develop QQ and membrane fouling control strategy. This in situ biostimulation strategy is able to increase the abundance of QQ bacteria without any limitation to mass transfer, and thus is expected to allow a better fouling control in MBR. In this project, efficient QQ biostimulants will be first screened, the key autochthonous QQ bacteria will be identified, the biostimulation mechanism will be analyzed, and the membrane fouling control strategy will be developed in order to realize an effective fouling control. The research outputs will provide theoretical basis and technical supports for QQ and fouling control in MBR.

膜污染问题是膜生物反应器（MBR）工艺中亟待突破的关键技术瓶颈。针对引起膜生物污染的微生物群体感应进行调控是一条极具前景的膜污染控制途径。目前MBR中群体感应调控多采用群体感应猝灭功能菌筛分辅以固定化的手段，其方法复杂，且固定化措施会阻碍功能菌获取营养、并阻碍其降解信号分子，严重限制群体感应猝灭的效果。针对上述问题，本项目拟采用投加化学刺激剂（特殊碳源）的手段，促进活性污泥体系中本土的群体感应猝灭功能菌原位增殖，并依此构建MBR中群体感应调控及膜污染控制策略。该原位生物刺激策略在保证功能菌丰度的同时能够避免固定化措施带来的传质限制，因而有望取得更好的生物污染控制效果。本项目拟通过高效群体感应猝灭刺激剂的筛选、关键本土功能菌鉴定和生物刺激机理的解析以及膜污染控制策略的构建，实现对MBR中生物污染的原位高效控制。研究成果可为群体感应调控及MBR中膜污染控制提供理论依据和技术支持。

膜污染问题是MBR工艺中的关键技术瓶颈，微生物群体感应猝灭是一条极具前景的膜污染控制途径。本项目研究了通过生物刺激方式实现MBR中群体感应调控，进而控制膜生物污染。通过筛选具有与信号分子相似化学结构的潜在刺激剂，得到γ-己内酯能够高效富集活性污泥中原位群感猝灭菌，并证明Rhodococcus菌为关键群感猝灭功能菌，qsdA为关键的功能基因，其能够编译内酯水解酶降解信号分子。通过考察不同MBR中生物刺激策略，发现初始投加群感猝灭功能菌复合连续投加刺激剂能够有效保证污泥混合液中功能基因含量、降解信号分子、减少EPS分泌、控制膜污染。在此基础上，进一步优化改进了生物刺激群感猝灭方法，开发了核壳双层结构载体，内核缓释包埋刺激剂、外壳固定化功能菌，避免了连续投加刺激剂的经济性弊端，并得到了良好的膜污染控制效果。此外通过对群感猝灭作用于MBR中亚硝化的考察，发现群感猝灭会提升亚硝化对不利条件（如抑制剂、低温）的敏感度，降低工艺氨氮去除效能。本项目可为活性污泥体系中群感调控及其对活性污泥体系中多过程协同作用机制提供理论依据及技术参考。