Optimization of bioethanol production using stress-tolerant yeast strains isolated from household alcoholic beverages (Tella, Tej, and Areke) and molasses (as substrate)

Abstract

Background Yeast strains that are tolerant to several environmental stresses are extensively employed to produce bioethanol from sugar-rich feedstock. Methods In our previous research findings, five wild indigenous strains of multi-stress tolerance yeast were isolated from traditional fermented alcoholic beverages (Tella, Tej, and Areke) in Ethiopia to the purpose of evaluate their potential use for bioethanol using sugarcane molasses as a substrate. Result The optimal parameters for maximum ethanol production were pH of 4.5, 25°Brix, 30°C, 4.0 g/l ammonium sulfate, supplement with yeast extract, and 72 h of incubation period. Under these optimum conditions, 13.13 ± 0.08% (v/v) ethanol was obtained. The yield of hydrous and anhydrous bioethanol from fermented molasses samples were produced at 94.20–95.60% (v/v) and 99.05–99.56% (v/v), respectively. Conclusion According to this finding, Saccharomyces cerevisiae isolate MUT15F, Saccharomyces cerevisiae isolate MUT18F, and Saccharomyces cerevisiae isolate R9MU strains have been good candidates for production of industrial bioethanol.