Optimization of bioethanol production from sorghum green malt and cane molasses using <scp> <i>Saccharomyces bayanus</i> </scp> in submerged cultivation

Abstract This study focuses on optimizing bioethanol production using Saccharomyces bayanus in a submerged culture medium containing sorghum green malt and cane molasses as mixed carbon sources. A Taguchi experimental design L 9 (3 4 ) was employed to evaluate the effects of the concentrations of cane molasses, urea, and CaCO 3 , as well as the initial pH, on bioethanol yield. The results demonstrated that molasses concentration and initial pH were the most significant factors influencing bioethanol production. The optimal treatment achieved a bioethanol concentration of 139.10 g/L after 48 h of fermentation, with a productivity of 2.90 g/(L · h) and a yield of 1.22 g of bioethanol produced per g of reducing sugars consumed. Additionally, the modified Monod model accurately described the fermentation kinetics, capturing trends in yeast growth and substrate consumption. This model is an essential tool for scaling up the bioethanol production process in continuous bioreactors. Results suggest that sorghum green malt, supplemented with cane molasses, provides a low‐cost, nutritionally complete, and environmentally friendly culture medium for bioethanol production.