Cyclic voltammetry study of a yeast-based microbial fuel cell

Microbial fuel cells (MFCs) using yeasts are known to produce less energy than those using bacteria. However, yeasts offer a plethora of advantages that can be used to MFCs profit. In this work, the electrochemical behavior of Zygosaccharomyces bailii was investigated by cyclic voltammetry, using a synthetic winery wastewater. The voltammograms revealed different oxidation-reduction peaks that could be associated to substrate oxidation/reduction and flavins production. The voltammograms also revealed an oxidation peak at 0.89 V vs SCE with a corresponding current of 418 μA. This peak current dependency with the scan rate indicated that the kinetics was ruled by diffusion and adsorption processes due to an irreversible electron charge transfer. This could be attributed to the yeast or to the electroactive metabolites excreted. The electroactive metabolites can play an important role in mediated electron transfer in yeast-based MFC systems for energy production and for biosensing and electrosynthesis applications. Cyclic voltammograms for a) sterilized SWW and Z. bailii cultured on SWW. • A MFC is a type of BES designed to treat a wastewater and produce energy. • The electrochemical behavior of Z. bailii was studied by CV using a SWW. • Z. bailii presented current peaks, indicating the production of metabolites. • The electroactive metabolites can play a role in mediated electron transfer. • This work reveals that yeasts could have a place in MFC systems.