生物阴极加速氯代烃污染物还原脱氯及作用机制

Chlorinated hydrocarbons (CHCs) are noteworthy for their characteristics of high toxicity, persistence and bioaccumulation. The reductive organohalide-respiring bacteria (ORBs), which use the chlorinated compounds as the terminal electron acceptor via microbial respiration, were proven of cost-effective and paramount importance as a potential CHCs-contamination treatment technology. However, some bottleneck problems, like the complex structure and high toxicity of CHCs, or lack of effective external electron transfer system, usually resulted in the low reductive dechlorination rate. To optimize ORB dechlorination activity and improve the reductive dechlorination rate, the applicant proposes a novel means by setting up the ORB-cathode catalytic system, where electrode is worked as a continuous electron donor and biofilm is formed on the electrode surface. In this proposal, we will employ three type ORB strains (Dehalococcoides sp. MB, Geobacter sp. AY or Dehalobacter sp. FTH1) to the cathode system, and investigate various impact factors to build up a controllable strategy on the formation of an electrochemically active ORB-cathode biofilm with the accelerated reductive dechlorination activity and efficiency. Meanwhile, we will reveal the electron transfer pathway and clarify the biochemical mechanism between electrodeand bacteria within the biocathode system, which as a result, to improve the ORB reductive dechlorination efficiency and explore the BES application in the reductive dechlorination of persistence organic compounds.

氯代烃是一类持久性高毒有机污染物。厌氧还原脱氯细菌（ORB）能够通过自身的呼吸代谢将氯代烃还原降解，但是氯代烃的高毒性、结构复杂性以及外源电子供体传递效率低等问题导致生物还原脱氯速度较慢。为了提高ORB的还原脱氯效能，本课题提出构建ORB-阴极催化系统，利用电极作为电子供体，使ORB在电极表面形成稳定可控的电化学活性生物膜，强化电子传递效率从而实现加速还原脱氯的研究思路。本课题拟重点研究典型ORB菌株（Dehalococcoides sp. MB，Geobacter sp. AY 和Dehalobacter sp. FTH1）形成电化学活性生物膜的方法，提高电极生物膜还原脱氯能力的调控策略，以及ORB-阴极催化系统加速氯代烃还原的催化规律。同时，揭示细菌与电极之间的电子传递途径，阐明生物阴极加速还原脱氯的分子机制，为提高氯代烃类污染物的生物脱氯效能提供理论依据和技术基础。

氯代烃是一类持久性高毒性有机污染物，具有高毒性和脂溶性。脱卤呼吸微生物能够通过自身的呼吸代谢将氯代烃分解转化，绿色环保无污染，但是氯代烃的毒性和结构复杂性以及外源电子供体传递效率低等问题导致生物还原脱氯速度慢、毒害性中间产物积累和降解效果差。基于此，研究通过构建有效的功能菌群富集分离方法提出了功能菌群复合厌氧还原和彻底脱毒卤代芳烃的技术思路与方法，并揭示了典型卤代芳烃污染物的厌氧脱毒规律和功能菌群互作机制；通过建立电刺激辅助强化氯代有机物还原系统实现了典型卤代烃污染物，如挥发性氯代烃、氯酚以及溴代阻燃剂等的快速还原脱毒；运用分子生态学和功能基因组学阐明了卤代烃的加速还原规律和菌体/电极之间的电子传递途径和机制。研究解决了由于氯代烃毒性和结构复杂性以及外源电子供体缺乏导致的生物还原脱氯速率慢、毒害性有机物积累的难题。研究为废水中持久性有机微污染的消减和去除提供了理论和技术依据。