Microbial electron transport and energy conservation - the foundation for optimizing bioelectrochemical systems.
Microbial electron transport and energy conservation - the foundation for optimizing bioelectrochemical systems.
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DOI：
10.3389/fmicb.2015.00575
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发表时间：
2015
影响因子：
5.2
通讯作者：
Krömer JO
中科院分区：
文献类型：
--
作者：
Kracke F;Vassilev I;Krömer JO
微生物电化学技术描述了利用电极-细菌相互作用进行生物技术应用的各种新兴技术，包括生产电力、废物和废水处理、生物修复和生产有价值的产品。每种应用的核心是微生物催化剂与外部电子受体和/或供体相互作用的能力及其代谢特性，使电子传递和碳代谢相结合。这也是一个关键的挑战。已发现多种微生物能够与固体表面或介体交换电子，但深入研究的微生物寥寥无几。特别是，从阴极到微生物的电子转移机制知之甚少，但对于微生物电合成等许多应用是必不可少的。我们分析了自然为金属呼吸细菌和产乙酸菌等生物提供的不同电子传输链，以及目前用于生物生产的标准生物技术生物。特别关注氧化还原与能量代谢之间的本质联系，而在研究生物电化学系统时往往忽略了这一点。讨论了细胞外电子交换在每个生物体的不同点所需的氧化还原电位以及对细胞氧化还原和能级的影响。关键化合物，如电子载体(例如，细胞色素、铁氧还蛋白、醌、黄素)被识别和分析，以确定它们在电极-微生物相互作用中的可能作用。这项工作总结了我们目前对电子传递过程的认识，并使用理论方法来预测不同的传递方式对能量代谢的影响。因此，它为研究界增加了对微生物电子传输可能性的重要基础理解，并将有助于优化和推进生物电化学技术。
Microbial electrochemical techniques describe a variety of emerging technologies that use electrode–bacteria interactions for biotechnology applications including the production of electricity, waste and wastewater treatment, bioremediation and the production of valuable products. Central in each application is the ability of the microbial catalyst to interact with external electron acceptors and/or donors and its metabolic properties that enable the combination of electron transport and carbon metabolism. And here also lies the key challenge. A wide range of microbes has been discovered to be able to exchange electrons with solid surfaces or mediators but only a few have been studied in depth. Especially electron transfer mechanisms from cathodes towards the microbial organism are poorly understood but are essential for many applications such as microbial electrosynthesis. We analyze the different electron transport chains that nature offers for organisms such as metal respiring bacteria and acetogens, but also standard biotechnological organisms currently used in bio-production. Special focus lies on the essential connection of redox and energy metabolism, which is often ignored when studying bioelectrochemical systems. The possibility of extracellular electron exchange at different points in each organism is discussed regarding required redox potentials and effect on cellular redox and energy levels. Key compounds such as electron carriers (e.g., cytochromes, ferredoxin, quinones, flavins) are identified and analyzed regarding their possible role in electrode–microbe interactions. This work summarizes our current knowledge on electron transport processes and uses a theoretical approach to predict the impact of different modes of transfer on the energy metabolism. As such it adds an important piece of fundamental understanding of microbial electron transport possibilities to the research community and will help to optimize and advance bioelectrochemical techniques.