ABSTRACT

Microbial electrogenic behaviour is well characterised in prokaryotes, including the exo-electrogenic soil bacteria (‘metal breathers’) and cyanobacteria, some of which can perform a light-induced donation of electrons to electrochemical devices. Two main methods of electron donation are proposed in these organisms; mobile electron shuttles (redox mediators), and direct electron transport where redox active moieties embedded in the bounding membrane of the organisms provide electrical connection. In this study a photosynthetic microbial fuel cell was used to investigate the mechanism of electron donation from six benthic cyanobacteria to an external electrode. There was no evidence of mobile electron shuttles donating electrons to the bio-electrochemical system using electrochemical analysis by linear sweep voltammetry in any of the species studied. This indicates the possibility that all the benthic species investigated may use direct electron transport as a mechanism of electron donation, which is better recognised in single-celled planktonic species.

摘要

微生物的电化学行为在原核生物中得到了很好的表征，包括外生电的土壤细菌（“金属呼吸器”）和蓝细菌，其中一些细菌可以将光诱导的电子捐赠给电化学设备。在这些生物中提出了两种主要的电子捐赠方法：移动的电子穿梭（氧化还原介体），以及直接的电子传输，其中嵌入在生物体边界膜中的氧化还原活性部分提供了电连接。在这项研究中，使用光合微生物燃料电池来研究从六个底栖蓝细菌向外部电极捐赠电子的机理。没有证据表明在任何研究的物种中，使用线性扫描伏安法通过电化学分析，可移动的电子穿梭将电子贡献给生物电化学系统。这表明研究的所有底栖生物都可能使用直接电子传输作为电子捐赠的机制，这在单细胞浮游生物中得到了更好的认识。