Bioethanol production from fruit wastes juice using millet and sorghum as additional fermentable sugar

Abstract

The increasing global energy consumption and carbon dioxide emissions from fossil fuel burning pose a significant issue in the modern era. Alternative energy sources are now necessary due to depletion of fuels derived from petroleum sources and their associated environmental impact. Fruit wastes can be utilized to make bioethanol which have the potential to decrease pollution and carbon dioxide emissions. In this study, bioethanol from a mixture of fruit wastes was produced through fermentation and distillation process. The physical pre-treatment of fruit wastes produced a juice with an average total soluble solids content of 9.7 ± 0.06 °Brix. Fruit wastes juice was enriched with sorghum and millet flour to provide additional fermentable sugars. Fruit wastes juice mixture with millet and sorghum produced an alcohol content of 25 % for the first 100 mL aliquot while fruit wastes juice mixture without millet and sorghum yielded 22 %. This confirms the potential of millet and sorghum as an additional fermentable sugar in the production of bioethanol. Re-distillation of the first aliquots improved the quality of bioethanol to 91 % alcohol content. Bioethanol production from fruit wastes offers significant environmental advantages including reduced landfill waste and reduced emissions of greenhouse gases due to decomposition. This process enhances resource efficiency by converting low-value agricultural residues into biofuel thus, supporting circular economy. Bioethanol is a renewable energy source that reduces carbon emissions and non-renewable resource reliance, thereby promoting sustainable energy practices. The use of fruit wastes mixture rich in natural sugars, supplemented with millet and sorghum as additional fermentable sugars, has improved bioethanol yield. Additionally, the application of a range of technologies from pre-treatment, fermentation to distillation that avoid use of corrosive chemicals has contributed to improved environmental management practices.