微生物电化学系统电子中介体

Electron Transfer Mediators in Microbial Electrochemical Systems

电化学活性微生物与电极之间的胞外电子传递在微生物电化学系统(microbial electrochemical systems,MESs)产能、生物修复等功能的实现中起着关键作用。目前,研究者对微生物胞外电子传递机理了解有限,限制了MESs的应用。相比于需要微生物功能蛋白与电极接触才能发生的直接电子传递,间接电子传递可通过具有可逆氧化还原活性的电子中介体(electron transfer mediators,ETMs)实现电子的传递,从而有效提高微生物胞外电子传递效率。在间接电子转移过程中,ETMs起着中间电子受体和中间电子供体的作用,即被还原后可将电子传递给最终电子受体并被重新还原;理论上每个ETMs分子可以循环数千次,因此ETMs对特定环境下终端氧化物(如铁离子)的循环有着极其显著的作用。本文系统总结了MESs中ETMs及间接电子传递机制近年来的研究进展,并且在此基础上探讨了ETMs在MESs中的研究趋势,以期推动MESs在生物修复、能源生产方面的实际应用。

Extracellular electron transfer（ EET） between electrochemically active microorganisms and electrodes plays a key role in microbial electrochemical systems（ M ESs） functioning of energy generation,bioremediation,etc. At present,researchers have a very limited understanding of the mechanism of EET,which is one of the major bottlenecks in application of MESs. Compared with direct electron transfer w hich requires a direct contact between microbial functional proteins and electrode,mediated electron transfer use electron transfer mediators（ ETMs）which have reversible redox activities accompanies by high-efficiency EET for transporting electrons. ETM s serve as the middle electron acceptor,once reduced,can transfer electrons to terminal electron acceptor where upon it becomes re-oxidized. In principle,ETMs molecules could cycle thousands of times,thus,have a significant effect on the turnover of the terminal oxidant（ e. g. iron） in certain circumstances. This review summarizes the recent advances of EET mechanisms w ith focus on mediated EET in M ESs. Furthermore,w e have highlighted the research trends of ETM s in MES,which will promote the practical applications of MESs in bioremediation,energy generation and so on.