著者

Luo PENG Xiao-Ting ZHANG Satoshi KAWAICHI De-Ti XIE Zhen-Lun LI

出版者

公益社団法人 電気化学会

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.83, no.8, pp.600-604, 2015-08-05 (Released:2015-08-05)

参考文献数

28

被引用文献数

2

---

In bioelectrochemical systems where the oxidative current is mediated by microorganisms, it remains unexplored as to whether low-potential substrates (e.g. formate) enable the anode to work at lower potentials. Due to implications to relevant engineering and natural systems, this study evaluated such possibility and underlying causes. The investigation compared voltammograms of the model exoelectrogen (to exclude the interfering factors in undefined cultures) Geobacter sulfurreducens grown with acetate and formate. G. sulfurreducens had an EM (half-saturation potential) of −0.138 ± 0.004 V vs. SHE when consuming acetate; an EM of −0.160 ± 0.002 V when utilizing formate. Such variation usually requires alternation in electrode reductase expressed by bacteria, according to the existing Nernst-Monod model with a single species of electron conduit. For both acetate- and formate-grown biofilm, non-catalytic voltammetries found multiple redox couples with distinct formal potentials. No clear evidence could support a hypothesis that the bacteria synthesized any different electron conduits when the substrate was changed. Significant changes in the relative abundance of high-potential and low-potential electrocatalytically active conduits were not observed as well. However, low-potential conduits showed elevated electrocatalytic activities in the formate-grown biofilm, which might induce the shift in apparent EM.