同型产乙酸菌/矿物协同驱动CO2固定的胞外电子传递及调控机制

微生物能够摄取矿物提供的电子进行胞外呼吸固碳，对解析全球碳元素循环和能量流动具有重要意义。同型产乙酸菌作为胞外呼吸-固碳微生物的典型代表，其胞外电子摄取途径及调控机制尚不明确。本研究拟选取典型的胞外呼吸-产乙酸菌，利用生物电化学系统模拟矿物胞外给电子过程，通过转录组学、遗传学手段，结合电化学、先进物化表征技术揭示产乙酸菌吸收利用胞外电子的关键蛋白及途径；系统研究外源性电子穿梭体、电子传递抑制剂、群感信号分子调控下的两菌共培养体系，从分子层面阐明胞外呼吸-产乙酸菌与其他胞外呼吸菌之间的竞争/协作机制；以纯菌和两菌共培养体系为研究对象，通过拉曼光谱-电镜联用技术揭示矿物表面生物膜的形成规律；对不同自然生境的胞外呼吸-产乙酸菌进行靶向富集，系统探究典型矿物对其生物膜的强化机制，提出矿物介导下微生物高效固定CO2的调控方法，从而为矿物/微生物体系在驱动碳循环和碳收支的作用解析提供新的理论基础。

Microorganisms can uptake electrons provided by minerals for extracellular respiration and carbon fixation, which is of great significance for the analysis of global carbon cycle and energy flow. Homoacetogens, as a typical representative of extracellular respiration and carbon sequestration microorganisms, its pathway of extracellular electron uptake and regulatory mechanism are not clear. In this study, we will select typical homoacetogens with capability of extracellular electron uptake, and simulate the extracellular electron delivery process of minerals by bioelectrochemical system. The key proteins and pathways of homoacetogens for absorbing and utilizing extracellular electrons, and the new respiratory pathway of CO2 fixation driven by minerals will be revealed by means of transcriptome and genetics, combined with electrochemistry and advanced physical and chemical characterization technologies. The molecular mechanism of competition / cooperation between homoacetogens and other extracellular respiratory bacteria will be elucidated by systematic study on the co-culture system of two bacteria under the control of exogenous electron shuttles, electron transfer inhibitors and quorum sensing molecules. With pure culture and co-culture system as the research object, respectively, we will reveal the formation laws of extracellular respiration biofilm on the surface of minerals by means of Raman spectroscopy and electron microscopy. Targeted enrichment of extracellular respiration and acetic acid producing bacteria in different natural habitats will be conducted. The enhancement mechanism of typical minerals on extracellular respiration carbon fixation biofilm will be systematically studied, and the control method of efficient CO2 fixation mediated by minerals will be proposed, which could provide a new theoretical basis for the analysis of the role of mineral / microbial system in driving carbon cycle and carbon budget.