Kinetic modelling and performance assessment of yeast microbial fuel cell under varying substrates for sustainable...

Optimizing the performance of Microbial Fuel cell (MFC) remains challenging because the metabolic activity of microbes still needs a clear vision, especially with complex-natured substrates used in real-world wastewater treatment systems. The substrate influences microbial growth and the MFC performance. This study examined the influence of various types of substrates, such as glucose, acetate, and starch (concentrations ranging from 5 g/L to 25 g/L), in a double-chambered MFC using Baker's yeast, Saccharomyces cerevisiae as a biocatalyst and Nafion-117 membrane as a proton exchange membrane (PEM). 20 g/L of acetate-fed MFC shows high performance; the observed OCV, current density, and power density are 861.9 mV, 1004.51 mA/m², and 252.69 mW/m², respectively. Overall, 65-81% COD removal was achieved, and the maximum coulombic efficiency of acetate-fed MFC at 20 g/L was 21%. One-way ANOVA analysis was conducted, and the analysis revealed the statistical significance of performance metrics. Hence, the electrochemical performance of MFC is influenced by various substrate concentrations. Aiba, Edwards, and Haldane kinetic models were used to study the substrate inhibition of MFC performance. The greater value of P_diff, K_i shows that strong inhibition occurred during the power generation. Kinetic results reveal that the starch inhibits more than the glucose and acetate. This work introduces novel approaches by highlighting the critical challenges of optimizing the substrate concentrations in yeast MFCs in batch mode. This MFC technology offers the double benefits of waste degradation and power generation, and also bridges sustainable energy recovery. Future integration technology promises potential application in the energy recovery sectors.