漫透射光谱电化学原位研究穿梭体介导的胞外电子传递过程

In-situ Examination of Electron Shuttle Mediated Extracellular Electron Transfer by Using a Diffuse-transmittance Spectroelectrochemical Method

微生物胞外电子传递是地球表层系统元素循环与能量交换的重要驱动力,穿梭体通过自身的氧化还原循环,介导并加速微生物与矿物之间的电子转移。但目前为止,穿梭体的实时氧化还原状态与胞外电子传递强弱之间的定量关系还不太清楚。因此,本研究搭建了漫透射光谱电化学测试系统,原位测试了典型穿梭体介导的胞外电子传递过程,探究了AQS氧化还原状态变化与电流强弱之间的关系。结果表明,在反应初期,电流的上升与AQS氧化还原状态密切相关,而反应中后期,AQS的氧化还原状态不再发生明显的变化,但电流仍然继续上涨,说明体系中除了AQS氧化还原状态以外,可能有其他更重要的因素在起着持续的作用。

The process of microbial extracellular electron transfer(EET)is an important driving force of element cycling and energy exchange in epigeosphere.The electron shuttle mediates and accelerates electron transfer between microbes and minerals via its redox cycling.However,the quantitative relationship between the redox status of electron shuttles and the strength of EET is still unclear.Hence,in this study,a diffuse transmittance electrospectroscopy test system was constructed.The electron shuttling process was in situ tested and the relationship between redox status of AQS and current intensity was analyzed.Results show that,in the initial stage of EET,the increase of current generation was closely related to the changing redox status of AQS.However,in the middle and late stages of the reaction,the current increased continuously while the AQS state didn’t change any more,indicated that other factors have a more important contribution for the current increasing.