A milliliter-scale yeast-based fuel cell with high performance

• The dual-chamber fuel cell of an mL scale was made for evaluation of yeast.
• In baker's yeast the maximum power per volume of the anode solution was 850 W/m3.
• The high maximum power was also obtained in Kluveromyces marxianus.
• The MFC powered by K. marxianus may be helpful for the effective use of woody biomass.

Microbial fuel cells are attracting attention as one of the systems for producing electrical energy from organic compounds. We used commercial baker's yeast (Saccharomyces cerevisiae) for a glucose fuel cell because the yeast is a safe organism and relatively high power can be generated in the system. In the present study, a milliliter (mL)-scale dual-chamber fuel cell was constructed for evaluating the power generated by a variety of yeasts and their mutants, and the optimum conditions for high performance were investigated. When carbon fiber bundles were used as an electrode in the fuel cell, high volumetric power density was obtained. The maximum power produced per volume of anode solution was 850 W/m3 under optimum conditions. Furthermore, the power was examined using seven kinds of yeast. In Kluyveromyces marxianus, not only the power but also the power per consumed glucose was high. Moreover, it was suggested that xylose is available as fuel for the fuel cell. The fuel cell powered by K. marxianus may prove to be helpful for the effective utilization of woody biomass.