Bioelectric fermentation applied to Saccharomyces cerevisiae: comprehension of metabolism and its effects on the ethanol production

Abstract

Currently, ethanol is the most consumed biofuel in the world. In Brazil there are three types of industrial processes for producing ethanol, known as "First Generation" (1G), "Second Generation" (2G) and corn ethanol. In the 1G ethanol production, sugarcane juice and molasses (resulting from the production of sugar) are converted to ethanol using industrial yeasts of the species Saccharomyces cerevisiae. In the context of trying to increase the fermentative yield, several works have shown that the application of an electric current during the fermentation can stimulate the metabolism of several microorganisms, including yeasts. There is also a technology in Brazil applied on an industrial scale (MBE2 technology of the company MAHLE Metal Leve S.A) that consists of a bioelectric system that operates in industrial fermenters and has resulted in a greater production of ethanol around 10%. Despite the various demonstrations of this phenomenon in laboratory and industrial scale, no study has studied the molecular mechanisms involved in the stimulation generated by the passage of an electric current in the fermentation medium. Although it has already been carried out on several bacteria, no study has been identified to try to produce genetically modified yeasts to increase the interaction with the electrodes. In this context, this project aims to study the modifications in the metabolic and transcriptional profiles of industrial yeasts that occur due to the application of electric current in the ethanol production and to perform genetic modifications to stimulate the increase of this interaction. (AU)