微生物胞外聚合物的还原活性及其环境效应

Microbial extracellular polymeric substances (EPS) are a major component of biofilms and play a key role in cell surface attachment and microhabitat formation to protect cells from environmental stresses. Despite the potential importance, little is known about the EPS-mediated redox transformation of environmentally concerned chemicals and the associated biological effects. This project is planned to investigate the reductive reaction of a series of high-oxidation-state heavy metals and organic compounds by microbial EPS using a batch reaction system combined with advanced analytic and spectroscopic techniques. The main objectives of the study are to reveal the underlying extracellular reduction mechanisms of the selected chemical species and the quantitative relationship between the reduction activity of EPS and their structural properties. The results obtained from the project will provide a better understanding of the pollutant-microbe interfacial interaction, the reactivity of natural dissolved organic matter (NOM), as well as the extracellular electron transfer process which is essential to many environmental geochemical reactions.

胞外聚合物是构成生物膜的重要组成部分，对于微生物的表面附着性能和应对环境应力十分重要，但目前针对微生物胞外聚合物介导条件下环境污染物的氧化还原过程及其效应知之甚少。本项目计划选取典型氧化态重金属和有机污染物，综合运用批次反应实验以及先进分析方法和谱学表征手段，揭示微生胞外聚合物的还原活性与其组成和结构间的关系，剖析微生物胞外聚合物对污染物的胞外还原机制。预期研究结果对于深刻认识污染物-微生物界面作用机制、天然溶解态有机质的反应活性、以及微生物胞外电子传递这一重要环境地球化学过程将具有理论指导意义。

申请人以污染物在微生物界面环境化学行为为重点，在胞外聚合物对多种高氧化态污染物的还原机制方面开展了深入系统的研究工作，取得了一些具有创新性的研究成果：揭示了EPS还原活性与其组成和结构间的关系，剖析了EPS介导污染物胞外还原的相关机制，并指出EPS的还原效应和屏障效应可能是微生物抵抗污染物细胞毒性的一种重要机制。2018年以来，在影响因子>2.0的SCI源刊物上发表论文11篇，其中第一作者、通讯作者论文10篇（包括Environ. Sci. Technol. 3篇）。所发表的SCI论文（总计11篇）近五年SCI正面他引113次。本项目研究结果提高了对细菌胞外还原高氧化态污染物的基本理解，也为污染物环境行为评估和生物修复技术发展提供了有效信息。