革兰氏阳性电活性菌的电子传递及其应用

Electron Transfer in Gram-Positive Electroactive Bacteria and Its Application

电活性菌将电子从胞内转移至胞外电子受体或者将胞外电子转移至胞内的过程为胞外电子传递,其在微生物群落间的电子传递及元素的地球化学循环过程中发挥重要作用。电活性菌的胞外电子传递研究前期主要集中于革兰氏阴性菌,由于革兰氏阳性菌与革兰氏阴性菌的膜结构/厚度明显不同,因此二者的电子跨膜传递途径差异明显。革兰氏阳性菌因分布广泛且可在高温、低pH、高pH和高盐等环境中生存,其电活性和电子传递机制也逐渐引起关注。本文归纳总结了革兰氏阳性电活性菌的电子传递类型,基于厚壁菌门、放线菌门和绿弯菌门的分类阐述胞外电子传递的研究进展,分析了革兰氏阳性电活性菌在污染物降解、生物能源和工业制品合成等方面的应用,并展望了未来的发展方向。

Microbial extracellular electron transfer(EET)is the process that electroactive microorganisms transfer electrons to an extracellular electron acceptor or receive electrons from the environment.EET is essential for interspecies electron transfer and also contributive to the biogeochemical cycling of elements and biotechnological applications in environments.Up till now,research on EET has been concentrated on Gramnegative electroactive bacteria,however,the EET pathway of Gram-positive electroactive bacteria remains limited.As the membrane structure between Gram-positive bacteria and Gram-negative bacteria are significantly different,the types of redox proteins and electron shuttles involved in the transmembrane transfer may be different.Gram-positive bacteria are widely distributed among environment and they can proceed EET in harsh condition e.g.high temperature,low pH,high pH and high salinity,therefore their electroactivity and EET have attracted great attention.In this review,we summarize the types of Gram-positive electroactive bacteria EET pathway,which include direct electron transfer and mediated electron transfer,the same as Gram-negative bacteria,but Gram-positive bacteria have much more diversities on redox proteins and electron shuttles.We elaborate recent development of EET pathways of Firmicutes,Actinobacteria and Chloroflexi,describe the applications in the degradation of pollutants,bio-electricity generation and biofuel production,then propose possible research directions in the future.