"How mediator compounds assist in electrofermentation with Clostridium beijerinckii strains"

• Grant number: 24/12271-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2024
• End date: November 30, 2025
• Field of knowledge: Biological Sciences - Biochemistry - Biochemistry of Microorganisms
• Principal Investigator: Valeria Reginatto Spiller
• Grantee: Marielle Tagiariolli Bovi
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 22/04024-0 - Cofermentation of organic and inorganic residues in biological and bioelectrochemical systems for obtaining bioproducts and electricity, AP.BIOEN.R

Abstract

Bioelectrochemical systems (BES) convert chemical energy into electrical energy (and vice versa) using microorganisms as biocatalysts. Microbial electrolysis cells (MEC) and microbial fuel cells (MFC) are the most well-known BES, with the forms of electron transfer between the microorganism and the electrode, as well as the role of mediators in this process, being the most studied. More recently, electrofermentation has emerged as a way to overcome the limitations of traditional fermentation processes. In electrofermentation, electrode polarization causes a modification in the profile and concentration of fermentation products and cellular biomass. It is not yet known exactly how the polarized electrode influences cellular metabolism, whether it is through electron transport, as in the most studied BES, or just by changing the redox potential (ORP) of the reaction medium. Even less studied is the role of electron mediating substances in this process. In other words, whether these substances could further increase the speed of fermentative reactions or act in maintaining the ORP. In a previous Scientific Initiation (IC) project (PIBIC), an increase in the production of organic acids in the electrofermentation of glucose by Clostridium beijerinckii was observed in the presence of methyl viologen as a mediator. Therefore, this project aims to understand the contribution of mediators in electrofermentation, aiming to increase the production of organic acids.