微生物电极呼吸对污染沉积物电场的调控效应及机制

The recently demonstrated phenomenon that electrons transfer from sediment to the top layer of water, termed sediment electric field (SEF), is a wide-spread and significant natural process. After the current focus on finding and exploring SEF, how to regulate and utilize SEF will be the upcoming core issue in this field. The oxidization of organic chemicals is the main electron source in SEF. Therefore, we hypothesize that the enhancement of SEF can stimulate the oxidative degradation of the organic pollutants in contaminated sediments. The previous studies indicated that microbial electrode respiration is potentially an effective pathway to regulate SEF. Therefore, this program plans to (1) describe the regulation of microbial electrode respiration on SEF using bioelectrochemical systems and micro-electrodes, (2) analyze the degradation efficiencies of organic pollutants in different SEF, to demonstrate the stimulating effects of SEF enhancement of the degradation of organic pollutants, and (3) screen the variation of structures of the microbial composition and environmental functional genes, as well as the valence state of the key electron mediators, elucidating the biogeochemical mechanisms underlying their inter-effects and relationships among the microbial electrode respiration, SEF and organic pollutant degradation. The results of this program will provide new insights into the microbial electron network in contaminated sediments and lead a new SEF-based bioremediation theory and technique development.

沉积物电场（Sediment electric field, SEF）是一种最近被证实的、普遍存在的、电子从沉积物向上覆水转移的重要自然现象。目前相关研究集中于对SEF的发现和认识，如何调控和利用这一自然现象将是下一阶段的核心问题。有机物氧化是SEF的主要电子来源。申请人认为，强化SEF可能会驱动并加速沉积物中有机污染物的降解。前期研究表明，微生物电极呼吸可能是调控SEF的有效途径。本项目将利用生物电化学和微电极系统验证微生物电极呼吸对SEF的调控效应；根据不同SEF中有机污染物的降解效率，确定强化SEF对有机污染物降解的驱动作用；通过监测微生物群落、功能基因结构和关键电子介体的变化过程，揭示微生物电极呼吸、SEF和污染物降解三者之间紧密相关、相互促进的生物地球化学机制。本项目研究结果有望进一步揭示污染水环境中的微生物电子传递网络，并引领一个基于SEF的新型的生态修复理论和技术研究方向。

水体沉积物的水-泥界面存在天然的氧化还原电位差，这一电位差是沉积物中电子自下而上转移的重要驱动力。通过研究该电位差驱动下的生物地球化学过程以及可能的调控策略对于认识自然过程以及污染水环境的治理具有潜在的重要意义。本项目基于沉积物的天然氧化还原电位梯度，通过构建微生物燃料电池调控氧化还原梯度并加速电子转移，从而达到加速污染沉积物中污染物降解的效果，并对该过程中微生物群落变化、C/S/Fe元素形态的转化转移、多环芳烃降解等生物地球化学过程的时空特征进行了系统解析，从而为加速污染沉积物的修复提供了重要理论和技术指导。在此基础上，项目还在珠三角的实际污染河涌中进行了测试，并取得了较好效果，为进一步形成适用的环保技术打下基础。本项目发表论文9篇，其中SCI论文6篇；申请专利3件，培养研究生3人，正高级职称1人，完成了预期目标。