ASSESSMENT OF ACID AND ALKALINE PRETREATMENT TECHNIQUES FOR OPTIMIZING BIOETHANOL PRODUCTION FROM LOCAL BANANA (MUSA ACUMINATE) PEEL BIOMASS FERMENTED WITH SACCHAROMYCES CEREVISIAE.

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The demand for energy and the need for improvement of the environment due to the use of fossil fuels have grown and made it more urgent to find other sources of energy and resources that are renewable and sustainable. In this study, the effectiveness of acid and alkaline pretreatment methods was evaluated to maximize bioethanol production obtained from banana (Musa acuminata) peel biomass using Saccharomyces cerevisiae. A 3x3 experimental design with three replications (Completely Randomized Design (CRD)) was used for the experiment, including a control, an acid pretreatment (1% H₂SO₄), and an alkaline pretreatment (1% NaOH). The banana peel powder (330 g/treatment) was subjected to pretreatment at 90-100C for 60 minutes, Hydrolysis with dilute sulphuric acid and fermentation at 30C for 72 hours. The results showed that, alkaline pretreatment (T₂) gave the maximum ethanol yield of (151.67 ± 0.88 mL/100g dry biomass), highest ethanol concentration (94.97 ± 0.15% v/v) and lowest specific gravity (0.790 ± 0.001). It also had the highest amount of initial sugar (18.50 ± 0.10 °Brix) and the highest sugar consumption (88.2%). The pre-treatment with acid (T₁) yielded moderate results and the untreated samples (T₀) exhibited very poor results in all cases. The pH decreased from 5.52 to 3.87–4.27 and titratable acidity increased from 1.10–1.18 g/L to 3.79–5.60 g/L, indicating the active metabolism of the yeast. A highly significant difference was found between the treatments for all parameters except initial pH by one-way ANOVA, which showed that the pretreatment methods were effective. According to the study, alkaline pretreatment at 1% NaOH is the best approach to optimize bioethanol production from banana peel biomass, resulting in bioethanol that complies with ASTM D4806 international fuel-grade standard. Future studies are suggested to maximize the pretreatment conditions by response surface methodology and to investigate the enzymatic hydrolysis and simultaneous saccharification and fermentation for maximum efficiency and economic feasibility. Keywords: Bioethanol, Banana peel biomass, Musa acuminata, Saccharomyces cerevisiae, Lignocellulosic biomass, Alkaline pretreatment, Acid pretreatment, Fermentation, Renewable energy, Agricultural waste valorization.