Microbial electric syntrophy accelerates conversion of chemicals ：Professor Kazuhito Hashimoto, Department of Applied Chemistry
June 5, 2012
Prof. Kazuhito Hashimoto at Department of Applied Chemistry in School of Engineering has been studying microbial fuel cells (MFCs), future clean-energy technologies in collaboration with Japan Science and Technology Agency and Tokyo University of Pharmacy and Life Sciences. MFCs are expected to be applied to biomass/electricity-conversion processes and energy-saving water-treatment processes, and have actively been studied worldwide. However, it has remained unanswered why microbes have the ability to transfer electrons to electrodes in MFCs.
We hypothesized that electrodes and wires also exist in the natural environments, and microbes use them to transfer electrons between each other. In order to address this possibility, we established binary cultures of model soil bacteria (Geobacter and Thiobacillus) in the presence of conductive iron-oxide (magnetite) particles, and found that magnetite substantially (over 10 folds) accelerated their cooperative catabolism. This indicates that electrons are transferred in magnetite particles, facilitating the connection of their metabolisms.
In the environment, a huge diversity of microbes inhabits, and they should establish complex interspecies interactions. However, since microbiology has been developed based on Pasteur’s isolation and pure-cultures techniques, knowledge on interspecies interactions is quite limited. Our finding will have broad impacts on our understanding of microbial interspecies interactions in nature and bases of strategies for developing more efficient bioenergy processes.