Long-term effect of set potential on biocathodes in microbial fuel cells: Electrochemical and phylogenetic characterization

• DOI: 10.1016/j.biortech.2012.06.017
• Publication Date: 2012-06-18T05:07:14Z
• Authors: Xue Xia; Yanmei Sun; Peng Liang; Xia Huang
• Keywords: Time Factors; Bacteria; Bioelectric Energy Sources; Molecular Sequence Data; Electrochemical Techniques; 01 natural sciences; 7. Clean energy; Aerobiosis; Oxygen; Electricity; Solubility; Biofilms; Biomass; Electrodes; Phylogeny; 0105 earth and related environmental sciences

The long-term effect of set potential on oxygen reducing biocathodes was investigated in terms of electrochemical and biological characteristics. Three biocathodes were poised at 200, 60 and -100 mV vs. saturated calomel electrode (SCE) for 110 days, including the first 17 days for startup. Electrochemical analyses showed that 60 mV was the optimum potential during long-term operation. The performance of all the biocathodes kept increasing after startup, suggesting a period longer than startup time needed to make potential regulation more effective. The inherent characteristics without oxygen transfer limitation were studied. Different from short-term regulation, the amounts of biomass were similar while the specific electrochemical activity was significantly influenced by potential. Moreover, potential showed a strong selection for cathode bacteria. Clones 98% similar with an uncultured Bacteroidetes bacterium clone CG84 accounted for 75% to 80% of the sequences on the biocathodes that showed higher electrochemical activity (60 and -100 mV).