Electrochemical activities of Geobacter biofilms growing on electrodes with various potentials. (20th January 2017)

• Record Type: Journal Article
• Authors: Li, Dao-Bo; Huang, Yu-Xi; Li, Jie; Li, Ling-Li; Tian, Li-Jiao; Yu, Han-Qing
• Is Part Of: Electrochimica acta. Volume 225(2017)
• Page Start: 452
• Page End: 457
• Publication Date: 2017-01-20
• Subjects: Geobacter sulfurreducens -- Biofilm -- Electrode potential -- Cytochrome c -- Electron transfer; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.12.146
• Languages: English
• ISSNs: 0013-4686

Abstract

Graphical abstract: Highlights: Dependence of current generation on potentials by G. sulfurreducens is complex with the optimum at +0.1 V. Unfavorable spatial distribution of biological activity within the biofilm at high potentials limits the current generation. Same cytochrome c species are used for electron transfer in the biofilms developed at all potentials. Abstract: Exoelectrogenic bacteria (EEB) play a central role in bioenergy recovery, biogeochemistry of elements, and polluting remediation. The electrochemical activity of EEB biofilm on electrode was proven to be dependent on the electrode potential, but the mechanism behind such a phenomenon is unclear. In this work, Geobacter sulfurreducens biofilms were developed at potentials ranging from −0.1 V to +0.6 V vs. standard hydrogen electrode to explore the profiles of potential regulation on G. sulfurreducens biofilm development and the electrochemical activity. We found that elevating the developing potential could improve the current generation by G. sulfurreducens biofilm until +0.1 V. At higher potentials less current was generated, although more biomass was formed on the electrode. The same cytochrome c species were synthesized for electron transfer in all biofilms, independent of the developing potential. Electrochemical experimental results and redox-sensitive staining imagings proved that the biofilms developed at +0.2 V–+0.4 V had greater cytochrome c contents and reducing capacities than the others. Current generation at high potentials was likely to be limited by both the metabolic rate and the electron transfer kinetics. These findings are useful for tuning the electrochemical activity of biofilm in catalyzing redox processes or generating electricity, which is crucial for the environmental and electrochemical application of EEB.