Yeast-based microbial biofuel cell mediated by 9,10-phenantrenequinone

Abstract Microbial fuel cells can be efficiently used for simultaneous cleaning of wastewater and generation of electricity. This research demonstrates the applicability of Baker yeast cells in the design of microbial biofuel cells. The applicability the 9,10-phenantrenequinone (PQ) as a redox mediator in the design of yeast-based microbial cell (MFC) for the improvement of charge transfer through the yeast cell membrane and cell wall towards the electrode was evaluated. The viability of bakers' yeast and pure Saccharomyces cerevisiae cell strains was investigated by evaluating the growth velocity of cells in the presence of a different concentration of PQ in solution. The growth curves of bakers' yeast showed that they were more resistant to PQ. Electrochemical measurements were performed with PQ as a redox mediator, which was (i) dissolved in solution and (ii) adsorbed on a graphite electrode. Differently modified graphite electrodes (namely: (i) non-modified, (ii) yeast-modified, (iii) modified by PQ and yeast) were evaluated. The modified electrodes were evaluated as anodes of MFC. The dependence of potential on external resistance and generated power of MFC was evaluated. Maximal open circuit potential was 178 mV at 7.8 mM of glucose and 23 mM of potassium ferricyanide. Maximal power of BFC calculated at the same conditions was registered at 56 mV, and it reached 22.2 mW/m2 (at 30 mM of glucose). The application of PQ as a redox mediator for yeast-based MFC improves electron transfer through the yeast cell membrane and cell wall towards electrode without any noticeable decrease of yeast cell viability.