Study of the extracellular electron transfer in fungi at unicellular scale

• Grant number: 23/06283-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2023
• End date: June 30, 2024
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Frank Nelson Crespilho
• Grantee: Guilherme Henrique Siqueira Ghiraldelli
• Host Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

Saccharomyces cerevisiae is a facultative anaerobic fungus capable of performing extracellular electron transfer (EET) to solid surfaces, as electrodes, and, therefore, it has been used as a biocatalyst in microbiological fuel cells. Despite recent studies about the EET mechanism of this microorganism, none addresses the individual contributions of each cell to the process. Hence, this project aims to study the EET of Saccharomyces cerevisiae at molecular and unicellular scales. For that, electrochemical and spectroscopic techniques will be used for redox and chemical characterizations of the fungus and the polymeric extracellular substance (EPS) secreted by it, as well as electrochemical scanning microscopy and scanning tunneling microscopy under electrochemical conditions, which allow the analysis of the topography, the cell-EPS-electrode interface and the electrochemical potential on the cell's surface in sub-nanometric and molecular scales. The results may contribute to the understanding of individual cellular redox events, providing cell surface and EPS information, for the first time, with spatial resolution while the processes occur under electrochemical control.