Intra/extracellular transmembrane electron transfer for bioelectric enhancement mediated by in-situ bio-FeS and polypyrrole coating

Abstract

This study involves the construction of an “inside-out” electronic network channel with in-situ formation of biogenic FeS (bio-FeS) nanoparticles in cells of Shewanella oneidensis MR-1 (S. oneidensis MR-1) and a coating of conductive polypyrrole (PPy) on the outer surface of entire cells. The microbial fuel cell driven by bio-FeS and PPy co-modified S. oneidensis MR-1 (FeS/PPy@MR-1) has a maximum power density 3.6 times higher than that of the native strain. Electrochemical analysis demonstrates that the modifications of bio-FeS and PPy markedly enhance the direct electron transfer and c-type cytochrome-bound flavin-mediated single-electron reaction pathways and expand the electron output flux. The electron-donating ability of FeS/PPy@MR-1 is 7 times greater than that of the native strain. Bio-FeS and PPy can mediate novel intra/extracellular transmembrane electron transport pathways independent of the traditional respiratory chain, bridge spatially discrete redox environments, and optimize electron transfer pathways to intracellular to extracellular transfer electrons rapidly and maximally. These findings provide insights into conductive nanomaterial-mediated intra/extracellular transmembrane electron transfer, which is critical for the environment and bioenergy fields.