Potential of Cellulomonas fimi for polysaccharide-fueled microbial fuel cells.

This study examined the feasibility of using Cellulomonas fimi and Shewanella oneidensis as microbial fuel cells 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. S. oneidensis could not utilize these fuels to generate electricity. 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. The accumulation of organic acid in the anode solution indicates insufficient electron transfer to the anode. To improve power generation efficiency, it may be necessary to enhance electron transfer from the cells to the anode, for example, by adding a mediator.