Investigating the electron shuttling characteristics of resazurin in enhancing bio-electricity generation in microbial fuel cell

Abstract

Microbial fuel cell (MFC) utilizes electro-active microorganisms to generate electricity from organic waste, promising a clean and sustainable energy source. However, the low power output severely restricts the scale of their application. Here, resazurin (RZ), a phenoxazine, is used as an electron shuttling mediator to enhance electrical transport at the anode electrode. Nearly a fourfold increase in power density of 1026.8 ± 1.6 mW/m2 (RZ-5) was obtained compared to the control MFC (272.7 ± 1.5 mW/m2). RZ transforms into resorufin (RR) and dihydroresorufin (DHRR) in the anode, responsible for the electron shuttling. It has the desired effects of shortening electrons’ diffusion path, decreasing the cell resistance, and enhancing bioelectricity production. It also has the added effect of promoting the growth of electro-active bacteria from Pseudomonas and Geobacter genus on the anode. Both genera are known for their efficient conversion of organics through direct and indirect electron transfer pathways.