CAREER: Electromicrobiological Studies Using Microbial Electrochemical Systems Capable of Sustainable Energy Production and Waste Treatment

将生物质，特别是有机废物转化为能源被认为是全球可持续能源组合的重要组成部分。新型微生物电化学系统，如用于发电的微生物燃料电池和用于制氢的微生物电解槽，已成为可再生能源生产和废物处理的潜在清洁技术。这些体系的主要特征和共同过程是微生物催化的电子从有机物到阳极的转移。提高阳极的电流输出对于所有这些工艺的成功应用至关重要，这需要对阳极上形成的生物膜有基本的了解。申请者的目标是，通过这个项目，通过系统地研究能够持续产生能源和废物处理的微生物电化学系统的高电流产生生物膜，来推进电子微生物工程的新兴领域。该项目将建立在申请人S实验室对混合细菌培养的最新研究基础上，该实验室展示了许多电力和氢气生产所需的特征。然而，微生物群落足够简单，可以保持对组成物种之间复杂相互作用的分析，从而为研究产生电流的阳极群落提供了一个理想的案例研究。拟议的研究计划的主要活动包括：(1)分离和鉴定微生物联合体中的优势菌株；(2)从形态、生理和电化学性质方面对分离的菌株进行表征；(3)阐明孤立的外电荷物的电子传递机制；(4)研究阳极联合体中不同细菌物种之间的相互作用关系。这是第一次对具有高电流产生能力的混合培养物进行系统研究，以确定优势细菌的身份、细菌向电极传递电子的机制以及细菌在群落中相互作用的方式。这项拟议的研究一旦成功完成，不仅将解决为什么混合培养产生的电流往往比大多数纯培养产生的电流大得多和更稳定的悬而未决的问题，而且还将导致发现用于电微生物学研究的高效新模式物种。此外，本研究的结论将丰富我们对微生物电化学系统中两个关键和鲜为人知的方面的理解：细胞外电子传递机制，包括生物介质、外膜细胞色素和细菌纳米线，以及阳极联合体内的代谢相互作用，涉及群体感应化学物质、介体和物种之间的电子供体交换。了解阳极生物膜内的基本代谢和电化学机制不仅有助于设计稳定和高效的能量产生系统，而且还将加速微生物电化学系统的发展，用于其他各种应用，如生物修复和生物传感。申请者在这一研究领域有良好的业绩和发表记录，并拥有成功执行拟议计划的资源。该项目的广泛影响包括教育、环境和经济，范围从当地到全球。与能源和环境可持续性有关的微生物电化学系统可以作为一个强大的平台，激励学生学习和理解微生物生态学、电化学、材料科学和工程的复杂概念，并解决未来的能源和环境问题。这个项目将通过开发动手操作的微生物燃料电池教学模块，显著提高研究生、本科生和K-12学生的科学推理技能。该项目还提供了一个独特的机会，将参与该项目的当地学生的教育经验与国家和全球关注的领域的尖端科学研究结合起来。将努力通过OSU SESEY计划招收和指导代表人数不足的少数族裔学生。在能源生产过程中伴随而来的废物处理承担着可持续发展的双重责任，提供来自可再生来源的能源，同时造福于世界各地的人类健康。最后，利用农业和工业废弃物生物质发电为农民和工业提供了一种新的经济利益来源，特别是偏远地区和发展中国家的农民和工业。这项工作的结果将通过发表在参考期刊和会议介绍上的出版物加以传播，也将在申请者网页上公布。

0955124LiuThe conversion of biomass, especially organic wastes, to energy is considered an essential part of a sustainable global energy portfolio. Novel microbial electrochemical systems, such as microbial fuel cell for electricity generation and microbial electrolysis cell for hydrogen production, have emerged as potential clean technologies for renewable energy production and waste treatment. The key feature and common process shared by these systems is the microbe-catalyzed electron transfer from organic matter to anodes. Enhancing current output from the anode is critical for the successful application of all these processes, which requires a fundamental understanding of the biofilm that develops on the anode. The applicants aim, through this project, is to advance the emerging area of electromicrobiological engineering by systematically investigating the high current-producing biofilm of a microbial electrochemical system capable of sustainable energy production and waste treatment. This project will build on the recent studies of a mixed bacterial culture in the applicant?s lab that exhibits many of the desirable features for electricity and hydrogen production. The microbial community is simple enough, however, to remain manageable for analysis of complex interactions between the constituent species, thereby providing an ideal case study for investigation of a current-producing anodic community. The main activities of the proposed research program include: (1) isolation and identification of the dominant bacterial strains in the microbial consortium; (2) characterization of the isolated strains in terms of their morphological, physiological, and electrochemical properties; (3) elucidation of the electron transfer mechanisms of the isolated exoelectrogens; and (4) investigation of the interactive relationships between different bacterial species in the anodic consortium. This is the first systematic investigation of its kind, wherein a mixed culture with high current-generating capability is studied comprehensively to determine the identities of the predominant bacteria, the mechanisms by which the bacteria transfer electrons to the electrode, and the ways in which the bacteria interact in the community. The proposed research, when successfully accomplished, not only will address the unanswered question of why the current generated by mixed cultures is often much greater and more stable than that generated by most pure cultures, but also will result in the discovery of highly efficient new model species for electromicrobiological studies. Furthermore, the conclusions from this research will enrich our understanding of two critical and poorly-understood aspects of microbial electrochemical systems: the mechanisms of extracellular electron transfer, including biogenic mediators, outer membrane cytochromes, and bacterial nanowires and the metabolic interactions within anodic consortia, involving quorum sensing chemicals, mediators, and exchange of electron donors between species. Understanding the fundamental metabolic and electrochemical mechanisms within the anode biofilm not only will enable the design of stable and efficient systems for energy generation, but also will accelerate the development of microbial electrochemical systems for diverse other applications such as bioremediation and biosensing. The applicant has a solid track record of performance and publication in this research field, and has the resources for executing the proposed program successfully. The broader impacts of this project are educational, environmental, and economic, and range from local to global in scale. The microbial electrochemical systems that relate to both energy and environmental sustainability can serve as a powerful platform for motivating students to study and understand complex concepts of microbial ecology, electrochemistry, and material science and engineering and resolve energy and environmental issues in the future. This project will significantly improve the scientific reasoning skills of graduate, undergraduate, and K-12 students through the development of hands-on microbial fuel cell teaching modules. This project also presents a unique opportunity for blending the educational experience of the local students involved in the project with cutting edge scientific research in an area of national and global concern. Efforts will be made to recruit and mentor underrepresented minority students through OSUs SESEY program. The concomitant treatment of waste during the energy generation process performs a double-duty of sustainability, providing energy from a renewable source while benefiting human health worldwide. Finally, generating energy from agricultural and industrial waste biomass offers a novel source of economic benefit to farmers and industries, especially those in remote areas and in developing countries. The results of this work will be disseminated through publications in refereed journals and conference presentations and also will be made available on the applicants webpage.