Saccharomyces cerevisiae as anodic biocatalyst for power generation in biofuel cell: influence of redox condition and substrate load

Bio (microbial) fuel cell (microbial fuel cell) with Saccharomyces cerevisiae as anodic biocatalyst was evaluated in terms of power generation and substrate degradation at three redox conditions (5.0, 6.0 and 7.0). Fuel cell was operated in single chamber (open-air cathode) configuration without mediators using non-catalyzed graphite as electrodes. The performance was further studied with increasing loading rate (OLRI, 0.91 kg COD/m³-day; OLRII, 1.43 kg COD/m³). Higher current density was observed at pH 6.0 160.36 mA/m² (OLRI); 282.83 mA/m² (OLRII)] than pH 5.0 (137.24 mA/m²) and pH 7.0 (129.25 mA/m²). Bio-electrochemical behavior of fuel cell was evaluated using cyclic voltammetry which showed the presence of redox mediators (NADH/NAD⁺; FADH/FAD⁺). Higher electron discharge was observed at pH 6.0, suggesting higher proton shuttling through the involvement of different redox mediators. The application of yeast based fuel cell can be extended to treat high strength wastewaters with simultaneous power generation.