铁还原菌在水资源再生与能源转化领域的研究进展

铁还原菌是一种典型的异化金属还原菌,广泛分布于海洋沉积物、陆地深地层等自然环境,该类细菌可以将铁氧化物中的Fe(Ⅲ)还原为Fe(Ⅱ),在铁、碳的生物地球化学铁循环中发挥重要作用。铁还原菌的末端电子不局限于Fe(Ⅲ),还可以是其他高价金属、有机污染物,可用于土壤、地下水的污染修复和毒性削减。在微生物电化学系统中,铁还原菌氧化有机物产生的电子直接传递给电极,可以产生电能。基于这种独特的胞外电子传递方式,衍生出了微生物燃料电池、微生物电解池、微生物脱盐电池、微生物燃料电池耦合芬顿反应以及光催化微生物燃料电池,常用于微生物发电、生物传感器、生物制氢、定向发酵、海水淡化、生物脱盐和污染物分解矿化。本文从异化铁还原菌的代谢机制、微生态作用、环境修复、水资源再生与能源转化四个方面,综述了铁还原菌的作用原理及国内外研究现状,分析论述了目前亟需解决的关键问题和未来的研究方向,以期为铁还原菌的基础理论研究和应用技术研发提供参考。

Iron-reducing bacteria in water regeneration and energy conversion

Iron-reducing bacteria are typical dissimilatory metal-reducing bacteria that are widespread in nature, including marine sediments and deep formations. These bacteria can reduce the Fe(III) of iron oxides to Fe(II) and play an important role in the biogeochemical iron cycle of iron and carbon. Aside from Fe(III), other high valence state metals and organic pollutants can also serve as the terminal electron acceptors of iron-reducing bacteria; therefore, these bacteria can be utilized for the pollution remediation of soil/groundwater and toxicity reduction. In microbial electrochemical systems, the electrons produced by the oxidation of organic matter by iron-reducing bacteria can be directly transferred to the electrode to generate electricity. Many microbial electrochemical technologies have been developed and are commonly used in wastewater regeneration and energy conversion fields, including microbial fuel cells, microbial electrolysis cells, microbial desalination cells, microbial fuel cells coupled with Fenton processes, and photocatalytic microbial fuel cells, which are utilized for microbial power generation, biosensors, biological hydrogen production, directional fermentation, seawater desalination, pollutant decomposition, and mineralization. Here, we summarize research progress on iron-reducing bacteria, including metabolic mechanisms, micro-ecological functions, environmental remediation, water regeneration, and energy conversion. We highlight outstanding questions in the study of iron-reducing bacteria and point out directions meriting future research. Generally, this review will aid both theoretical and applied studies of iron-reducing bacteria.