重金属胁迫下EAB同时高效去除重金属、产氢与固定CO2一体化过程与调控机制

With the development of modern industry and rapid urbanization, heavy metal contamination, more energy requirement and unprecedented climate change influenced by elevated concentrations of CO2 have become worldwide environmental concerns and compelled the research world to focus on technologies for heavy metal removal, hydrogen production and CO2 biosequestration. Together with research progress on electrochemically active bacteria (EAB) on the cathodes of bioelectrochemical systems (BES), process and regulation of simultaneously efficient heavy metal removal integrated with hydrogen production and CO2 biosequestration/reduction are proposed based on the catalysis of EAB isolated from the cathodes of BES and stressed by heavy metal. While critical influence parameters are evaluated for simultaneously efficient system performance, relationships between cathode-EAB electron transfer and heavy metal removal, hydrogen evolution, or CO2 biosequestration are quantitatively clarified based on the EAB activities in response to heavy metals, pH and HCO3- with the addition of typical metabolic inhibitors. Typical extracellular and intracellular enzymes associated with these EAB are quantitatively explored in addition to the analysis of composite of extracellular polymeric substances in terms of total protein and polysaccharide in order to illuminate the physiological and biochemical process mechanisms. Transcriptomic and proteomic analysis for these EAB is further performed to clarify the molecular biology mechanism. This study not only enriches the in-situ bioremediation principles for heavy metal polluted environment, and metal resistance technologies for biohydrogen and CO2 biosequestration, but also broadens the conceptual cathodic EAB and the applicable field and scope of BES. As a consequence, the theoretical and practical significance is evident.

基于重金属污染、清洁氢能需求、温室气体CO2累积的现实，结合生物电化学系统(BES)阴极电化学活性菌(EAB)研究现状，本项目提出重金属胁迫下的纯菌EAB高效去除重金属、产氢与固定CO2一体化过程。内容包括：基于典型重金属胁迫下的阴极EAB筛选，探讨其高效去除重金属、产氢与固定CO2一体化过程及关键影响因素；通过定量描述典型代谢抑制剂作用下的重金属、pH与HCO3-对EAB性能影响，总结电极EAB间电子传递与EAB高效去除重金属、产氢、及固定CO2间关系与作用；通过定量EAB胞外聚合物及胞内外典型酶活性，阐明EAB特性的生理生化作用机制；基于EAB的转录组基因与蛋白质组学解析，阐明EAB特性的分子生物学作用机制。本研究工作的开展将不仅丰富重金属污染环境的原位生物修复理论，发展耐受重金属的生物制氢与固定CO2技术，而且能拓展阴极EAB内涵及BES应用领域和使用范围，具有重要理论和现实意义。

在国家自然科学基金面上项目(No. 21777017)资助下，以耐受重金属的13株电活性菌(EAB)为研究对象，实现了生物电化学系统(BES)阴极去除重金属同步产氢或还原无机碳为乙酸过程，系统考察了电流、(混合)重金属浓度条件下的EAB去除重金属以及亚细胞水平的不同价态重金属分布(Bioelectrochemistry 2018, 122: 61-68; Front Environ Sci Eng 2018, 12: 7)；阐明了电极生物膜和游离细胞依赖于菌株种类、电流、金属浓度及胞外聚合物(EPS)和胞内酶活性的生理生化作用机制(J Hazard Mater 2019, 371: 463-473; Sci Total Environ 2019, 666: 114-125; Chemosphere 2020, 243: 125317)；发现了磁场与担载Fe3O4通过调节EAB分泌EPS和类细胞色素、提高电流和介体氢气产量(Biochem Eng J 2020, 155: 107467; Inter J Hydrogen Energy 2021, 46: 7183-7194; Environ Res 2021, 193: 110550)、及不同进料方式(Environ Eng Sci 2020, 37: 439-449)影响BES效能的策略和方法；明晰了EAB组装半导体WO3/MoO3/g-C3N4或Ag3PO4/g-C3N4及原位生成H2O2在BES高效稳定还原无机碳产乙酸/去除Cr(VI)的作用机制(Appl Catal B-Environ 2020, 267: 118611; 2021, 284: 119696; Chem Eng J 2021, 406: 126786)。研究结果丰富了重金属污染环境的生物修复理论和生物制氢或碳减排/碳中和技术，拓展了EAB内涵和BES应用领域及使用范围，具有重要理论和现实意义。共发表第一标注SCI论文12篇，IF总和105.8，均篇IF 8.8；授权发明专利2项；发表第二标注SCI论文11篇、专著1部；发表第三标注SCI论文2篇。