Potential of <i>Cellulomonas fimi</i> for polysaccharide-fueled microbial fuel cells

To generate power from various biomass using microbial fuel cells (MFCs), microorganisms with high potential are essential. Therefore, this study examined the feasibility of using Cellulomonas fimi and Shewanella oneidensis as MFCs fueled by starch, cellulose, chitin, and chitosan. To our knowledge, this is the first report of power generation using C. fimi fueled by these polysaccharides other than cellulose, furthermore the first report of S. oneidensis fueled by chitosan. No differences were observed in the power generation capacities between C. fimi and S. oneidensis when chitin and chitosan were used. However, C. fimi demonstrated effective power generation from starch and cellulose, showing a maximum current density of 17.4 mA m-2 for starch and 38.8 mA m-2 for cellulose. Shewanella oneidensis could not utilize these fuels. Power generation using C. fimi fueled by starch and cellulose produced acetic acid, lactic acid, and formic acid. However, when chitin and chitosan were used, only acetic acid was produced. These results indicate that electron transfer from C. fimi to the anode may be inefficient. To improve power generation efficiency, it may be necessary to enhance electron transfer from the cells to the anode, e.g. by adding a mediator.