Production of bioethanol from molasses by varying brix and yeast concentration

Abstract The study aimed to determine the optimal yeast concentration and growth pattern using the yeast growth curve and to evaluate bioethanol yield from molasses through fermentation with varying Brix levels and yeast concentrations. Bioethanol was produced from sugar mill molasses using Saccharomyces cerevisiae , which converts sugars into ethanol and carbon dioxide. Variations in Brix levels and yeast concentrations influence alcohol yield and volume, necessitating further research to identify optimal conditions for efficient bioethanol production. Seven yeast concentrations (1%, 1.5%, 2%, 2.5%, 3%, 3.5%, and 4%) were tested by measuring optical density (OD) to select the optimal concentration. This concentration was then applied in fermentation with Brix variations of 15%, 17%, and 19% for 72 hours, followed by distillation to obtain bioethanol. Ethanol content was measured using a UV-Vis spectrophotometer, resulting in bioethanol yields of 0.145%, 0.166%, and 0.180% for 15%, 17%, and 19% Brix, respectively. The highest ethanol content (0.180%) was achieved with 19% Brix and 4% yeast concentration after 8 hours of fermentation. These findings are expected to improve the efficiency of bioethanol production from molasses, supporting renewable energy development and reducing reliance on fossil fuels.