Bioelectrosynthesis of renewable energy carriers from carbon dioxide

可再生燃料的微生物电合成（生物电合成）是一个新兴的研究领域，引起了研究人员的极大关注，这可以从致力于该领域的出版物数量的指数增长中得到证明。在微生物电合成中，电活性微生物作为生物催化剂催化阴极反应（如CO2还原）。重要的是，电活性微生物也被证明与金属催化剂相互作用，从而提高生物反应速率。演示了几种生物电化学阴极转化，包括CO2转化为CH4（电甲烷生成）和C2-C4化合物（如乙酸、乙醇和丁醇）的电合成。尽管近年来我们对微生物燃料电池（mfc）等生物电化学系统阳极上的直接和间接电子转移机制的了解有了显著的进步，但对生物阴极上的电子转移机制知之甚少。此外，很少有现有的研究致力于生物阴极建模。所有现有的关于电甲烷生成和从二氧化碳中生产C2-C4化合物的研究都仅限于实验室规模的概念验证演示。特别是，多次电甲烷生成研究表明，要么是CO2的不完全转化，要么是阴极催化（或生物催化）产生H2。拟议的研究计划旨在通过应用全面的系统工程方法来推进对生物电化学过程的理解和二氧化碳转化为可再生能源载体的商业化，其中实验工作与建模和操作优化相结合，旨在最大限度地提高产量，降低操作成本，并为稳定的系统运行开发实用的控制算法。将追求以下目标：(i)加强对途径和电子转移机制的了解，并确定能够将CO2还原为CH4和C2-C4化合物的电活性微生物；发展能够充分描述生物阴极动力学和电活性生物膜形成的动态数学模型；（iii）将数学模型应用于生物电合成过程的操作优化和实时控制，包括对所提出的在线过程控制算法的实验验证。

Microbial electrosynthesis (bioelectrosynthesis) of renewable fuels is an emerging research area, which attracts significant attention of researchers, as can be evidenced from the exponential growth in the number of publications dedicated to this area. In microbial electrosynthesis, electroactive microorganisms catalyze cathodic reactions (e.g. CO2 reduction) acting as biocatalysts. Importantly, electroactive microorganisms were also shown to interact with metal catalysts resulting in enhanced bioreactions rates. Several bioelectrochemical cathodic transformations were demonstrated, including CO2 conversion to CH4 (electromethanogenesis) and electrosynthesis of C2-C4 compounds such as acetate, ethanol, and butanol. Although our knowledge of direct and indirect electron transfer mechanisms at the anode of such bioelectrochemical systems as microbial fuel cells (MFCs) significantly advanced in recent years, much less is known about the electron transfer mechanisms at a biocathode. Also, very few existing studies are dedicated to biocathode modeling. All existing studies on electromethanogenesis and production of C2-C4 compounds from CO2 are limited to laboratory-scale proof-of-concept demonstrations. In particular, multiple electromethanogenesis studies showed either an incomplete conversion of CO2 or presence of H2 catalytically (or biocatalytically) produced at the cathode. The proposed research program seeks to advance the understanding of bioelectrochemical processes and commercialization of CO2 conversion to renewable energy carriers by applying a thorough system engineering approach, where experimental work is combined with modelling and operational optimization aimed at maximizing yields, reducing operational costs, and developing practical control algorithms for stable system operation. The following objectives will be pursued (i) Enhanced understanding of pathways and electron transfer mechanisms, and identification of electroactive microorganisms capable of CO2 reduction to CH4 and C2-C4 compounds; (ii) Development of a dynamic mathematical model capable of adequate description of the biocathode kinetics and electroactive biofilm formation; (iii) application of the mathematical model to operational optimization and real-time control of the bioelectrosynthesis process, including experimental validation of the proposed on-line process control algorithms.