Bioethanol production using sugar beet (Beta vulgaris) juice as substrate by stress-tolerant yeast strains isolated from Areke

Abstract

Traditionally fermented beverages are potential sources of industrially relevant microorganisms. Among alternative energy sources, biofuels have gained increasing attention as replacements for fossil fuels. This study aimed to investigate the potential stress-tolerant yeast strains isolated from Areke for bioethanol production using sugar beet (Beta vulgaris) juice as substrate. In the current study, four wild yeast strains capable of withstanding multiple stresses were isolated from Areke. Fresh sugar beets were gathered from a local supplier in Debre Markos town, and the physicochemical characterization of the sugar beet juice was determined using standard methods. Ethanol production was optimized using four selected Saccharomyces cerevisiae strains, namely MUA1F (OR209275.1), MUA3F (OR209274.1), MUA11F (OR209277.1), and MUA15F (OR209276.1), using sugar beet juice as the substrate. Most Saccharomyces cerevisiae strains showed better fermentation performance under high osmotic pressure, ethanol concentration, and temperature stress than the Methera standard yeast in ethanol production. Fermentation optimization showed that these native Saccharomyces cerevisiae strains efficiently converted sugar beet juice to ethanol without requiring many pretreatments, indicating their potential for industrial applications. These findings suggest that the Saccharomyces cerevisiae isolates MUA3F and MUA15F should be further assessed, improved, and optimized for industrial bioethanol production because of their fermentation potential.