The role of extracellular polymeric substance matrix on Saccharomyces cerevisiae bioelectricity

Saccharomyces cerevisiae is one of the first microorganism established to be able to convert chemical energy into electricity, however its extracellular electron transfer (EET) mechanism was still unclear. Here, we show how yeast strains extracellularly transfer electron to an electrode surface. We observed yeast cells adsorption on solid surfaces occurs through the extracellular polymeric substance (EPS) network, and EET process takes place by redox species mostly confined on the electrode surface. We demonstrated that a flavoprotein is present in the Saccharomyces cerevisiae s acute accent EPS and is responsible by non-diffusive extracellular electron transfer through the EPS electroactive microenvironment. It is proposed EPS acts as a polyelectrolyte for multistep electron-transfer between flavoproteins and consequently for the Saccharomyces cerevisiae EET and bioelectricity generation. The elucidation of this mechanism combined to electrode engineering can contribute to the advance of biosystems in green energy generation, such as microbial fuels. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

It has been found that Saccharomyces cerevisiae transfers electrons externally to electrode surfaces through an extracellular polymeric substance network, with flavoproteins responsible for non-diffusive extracellular electron transfer. This mechanism could advance bioenergy generation through microbial fuels.