Bioethanol production from leftover food by yeasts isolated from fruit at Ambo University, Ethiopia

As fossil fuel emissions have a detrimental effect on the environment, renewable energy sources are crucial in replacing conventional energy sources. Isolation and characterization of yeast and assessing their potential for bioethanol production from leftover food are the main aim of this research. The yeasts were isolated from fruits and characterized using a conventional microbiological technique, based on how well they were able to ferment and produce bioethanol from glucose. Four yeast isolates were selected for bioethanol production based on the bioethanol production potential. Yeast isolate BaII07 yielded (85.5 ± 6.6) bioethanol from 3 g of rice leftover, while it produced only 32.9 ± 6.6 from 4 g of qinche leftover. Yeast isolate OrII20 gave the highest bioethanol from 3 g of rice (105 ± 6.6), whereas it produced only 52.6 ± 6.6 from qinche 2 g and 4 g. OrII23 and Pa II36 yielded bioethanol from 72.3 ± 6.6 to 39.5 ± 11.4, from different leftover foods evaluated. In this research, four efficient bioethanol producing yeasts from leftover food were isolated and characterized by conventional methods. The elite yeast isolate OrII20 produced up to 105 ± 6.6 g/L ethanol from rice leftover food. This contributes to curve the problem of managing solid organic wastes without harming the environment. Accordingly, this study has two advantages; by preventing the buildup of solid organic waste in the environment, it first helps to ensure environmental sustainability. Second, it produced bioethanol, which can improve or replace conventional energy sources and reduce greenhouse gas emissions because it is made from renewable sources.