中文摘要：

微生物是土壤、湖泊、沉积物中重要的活性物种。胞外呼吸是微生物主要的能量代谢方式，是微生物与胞外受体间进行电子传递的主要路径。胞外电子传递过程是胞外呼吸作用的重要组成部分，影响着环境中的物质转变和能量交换。研究发现胞外电子传递方式主要包括直接电子传递和间接电子传递两大类。其中，直接电子传递方式主要分为直接接触、纳米导线和纳米导线网络；间接电子传递以穿梭体介导的电子传递为主。腐殖质是自然界中重要的氧化还原活性物种，能作为穿梭体参与间接电子传递过程。已有的研究表明穿梭体能影响单菌体系微生物胞外电子传递过程，但其影响微生物群落胞外电子传递过程的研究更具实际意义。本实验以浅海沉积物为研究对象，构建微生物燃料电池（Microbial Fuel Cell，MFC），结合电化学方法研究在核黄素、AQDS、2-HNQ3种穿梭体介导下，微生物群落燃料电池的输出电压、极化曲线、功率密度等电化学参数的变化情况，以此来表征穿梭体对微生物群落胞外电子传递过程的影响。研究结果表明：（1）浅海沉积物中存在能进行胞外呼吸的微生物且能成功启动微生物燃料电池；（2）穿梭体的表观电极电位越低，其介导的微生物燃料电池的输出电压越高，此研究结果与纯菌体系相同；（3）纯菌体系中穿梭体的表观电极电位是胞外电子传递速率的决定因素，但在群落体系中并不成立。

英文摘要：

Microorganisms are the most important active species in soil,lakes and sediments.The main form of microbial energymetabolism was extracellular respiration,which was an important electron transfer pathway between microbe and extracellularelectron acceptors.Extracellular electron transfer(EET),the essential part of extracellular respiration,can affect the conversion ofmatter and exchange of energy.In general,several extracellular electron transfer mechanisms have been proposed:direct electrontransfers and indirect electron transfers.Direct electron transfer pathways contain direct contact,nanowires and nanowire networks.While,indirect electron transfer pathways mainly related with electron shuttles(ESs).Humus,an important redox active species innature,can act as ESs participating in indirect electron transfer pathways.It was reported that ESs had an impact on EET in the singlebacteria system.While,ESs-mediated EET of microbial community has more practical significance.In this study,microbial fuel cells(MFCs)were constructed by inoculating shallow-sea sediments for revealing the way of ESs affecting on the EET of microbialcommunity.Electrochemical method was used to study the output voltage,polarization curve,power density of MFCs with differentelectron shuttles,riboflavin,AQDS and2-HNQ.The results are as follows,(1)there are many extracellular respirationmicroorganism existing in shallow-sea sediments with the ability to activate the MFCs.(2)The apparent potentials of ESs havenegative correlation with the output voltages of the MFCs inoculating shallow-sea sediments,which was the same with the singlebacteria system.(3)Differing from the single bacteria system,the apparent potentials of ESs may not be the key factor for the rate ofEET in the MFCs inoculating shallow-sea sediments anymore.