微生物胞外呼吸电子传递机制研究进展  

Electron transfer mechanism of extracellular respiration:a review

作　　者：马晨[1,2,3] 周顺桂[1] 庄莉[1] 武春媛[1] 

机构地区：[1]广东省生态环境与土壤研究所,广州510650 [2]中国科学院广州地球化学研究所,广州510640 [3]中国科学院研究生院,北京100049

出　　处：《生态学报》2011年第7期2008-2018,共11页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(31070460;40801119);国家863计划项目(2009AA05Z115)

摘　　要：胞外呼吸是近年来发现的新型微生物厌氧能量代谢方式,主要包括铁呼吸、腐殖质呼吸与产电呼吸3种形式。微生物胞外呼吸与传统的有氧呼吸、胞内厌氧呼吸存在显著差异。其电子受体多以固态形式存在于胞外;氧化产生的电子必须通过电子传递链从胞内转移到细胞周质和外膜,并通过外膜上的细胞色素c、纳米导线或自身产生的电子穿梭体等方式,最终将电子传递至胞外的末端受体。胞外呼吸的本质问题是微生物与胞外电子受体(铁/锰氧化物、固态电极或腐殖质等)的相互作用,即微生物如何将胞内电子传递至胞外受体。胞外呼吸的研究丰富了人们对微生物呼吸多样性的认识,同时在污染物原位修复及清洁生物能源提取方面具有重要应用前景,是当前研究的热点问题。总结了胞外呼吸类型和胞外呼吸菌的多样性,重点阐述了胞外呼吸的电子传递过程,并提出了其应用前景及今后的研究方向。It has been well known that microbes can generate energy utilizing various strategies.However,only recently,it has become clear that a growing number of microbes involve electron transfer to or from extracellular substrates.This novel microbial metabolism is so termed as ＂extracellular respiration＂,in which microbes oxidize organic matters to carbon dioxide and conserve energy for microbial growth coupling with transfer of electrons and protons along the respiratory chain（a series of enzymes that function to transport protons and electrons inside the cells） to reduce extracellular electron acceptors.Different from the conventional aerobic and anaerobic respirations,the unique characteristic of extracellular respiration is its capability to use extracellular substrates as terminal electron acceptors.The well-known examples are Fe（Ⅲ）/Mn（Ⅳ） respiration,humus respiration and electricigenic respiration,in which iron/manganese（hydr）oxides,humic substances and solid electrodes are served as the extracellular electron acceptors.＂Extracellular electron transfer＂ is defined as the process in which electrons derived from the oxidation of electron donors are transferred to the outer surface of the cell to reduce an extracellular terminal electron acceptor.In the first step for electrons travelling between cells and extracellular substrates,electrons are required to be transferred through electron carriers in the periplasm and come across the non-conductive cell walls,which involves various functional genes and protein complexes（such as multi-hemes c-type cytochromes inside the cell）.Afterwards,electrons can be directly or indirectly transferred from the outer membrane to the extracellular electron acceptors via different mechanisms.In general,three main electron transfer mechanisms have been proposed：（1） direct electron transfer to electron acceptor via membrane-bounded cytochromes;（2） direct electron transfer to electron acceptor through conductive bacterial pili（＂nanowires＂�

关 键 词：胞外呼吸 电子传递链 细胞色素C 细胞外膜 

分 类 号：Q935[生物学—微生物学]