Essential factors that affect bioelectricity generation byRhodopseudomonas palustrisstrainPS3in paddy soil microbial fuel cells

A plant-associated phototrophic bacterium,R. palustrisstrain PS3, was inoculated into a soil-based MFC to generate electricity. We evaluated the performance of this soil-based microbial fuel cell (MFC) and elucidated the essential factors that contributed to power generation. PS3 showed the potential to enhance power generation, especially when the apparatus was operated in a sealed chamber with illumination.We deduced that the improved power performance was due to the enhanced electron transport through the living electrode that was grown as a PS3 biofilm via photoheterotrophic metabolism. In addition, we suggested that the interplay between phototrophic fixation of ambient CO(2)and anaerobic oxidation of ferrous iron in soil was also involved in the increased power output. We implemented CMOS (complementary metal-oxide-semiconductor) technology with the soil-based MFC to harvest energy in a more efficient and stable manner. The above system is expected to provide a potentially low-cost and low-energy system with a high power conversion efficiency for practical applications in the future.