Power Generation and Anode Bacterial Community Compositions of Sediment Fuel Cells Differing in Anode Materials and Carbon Sources

摘要

For monitoring environmental conditions of remote places, sustainable power generators are necessaryto power telemetry sensor systems. A sediment microbial fuel cell (SMFC) is a device that produceselectricity biologically from organic matters in sediment. Because a SMFC utilizes sediment organicmaterials and microbial catalysts in river or oceanic sediment, a SMFC can be a feasible solution forsustainable power generation in remote places. However, oligotrophic sediment conditions often limitenergy source supply, resulting in insufficient power output for operating electronic devices. Theobjective of this study is to investigate power generation and anode bacterial communities of SMFCswith different anode materials and carbon sources for enhancement of power output and longevity ofSMFCs. Four kinds of anode electrodes were tested in SMFCs; a magnesium electrode (M), amagnesium electrode supplied with chitin particles (M+C), a graphite electrode (G), and a graphiteelectrode supplied with chitin particles (G+C). Average maximum power density was highest in Mg+C-2 -2 -2 (1878 982 mW m ), followed by M (848 348 mW m ), G+C (1.9 0.6 mW m ) and G (0.7 0.6-2 mW m ). Maximum power densities of the magnesium electrodes were ~1,000 times larger than thoseof the graphite electrodes. The chitin supplement increased maximum power densities by 121% in themagnesium anodes and 164% in the graphite anodes on average. A magnesium electrode in M+Cdegraded more slowly than that of M. Anode bacterial communities of the magnesium anodes werediverse than the graphite anodes, and the supplemented chitin greatly influenced anode bacterialcommunity compositions. Although magnesium corrosion was a main process of power production inthe magnesium-anode SMFCs, species-level anode bacterial communities were very different betweenM and M+C. Anode bacterial communities of the chitin-absent anodes had larger richness estimatesand diversity estimates than those of the chitin-supplemented anodes, suggesting that the saturatedcarbon source greatly simplified anode bacterial communities.