Antibacterial Efficacy of Bioethanol Extracted from Sugarcane Juice and Corn Cob Against Escherichia coli

Abstract

This study is aimed at comparing the bioethanol produced from Saccharum officinarum L. and Zea mays L. in terms of their yield, disinfectant potential and antibacterial efficacy against Escherichia coli. The feedstocks were sourced from the Katsina Central market, Nigeria, during the 2025 harvest season. Corncobs were pretreated by dilute acid steam explosion using 1.5% H₂SO₄ at 121°C for 60 min, followed by enzymatic hydrolysis with cellulase and hemicellulase at 50°C for 72 hours. Sugarcane juice was liquefied and saccharified using α-amylase and glucoamylase. Both hydrolysates were fermented with Saccharomyces cerevisiae at 30°C for 72 hours and distilled by fractional distillation. Sugarcane juice outperformed corn cobs in process efficiency, yielding 72.8 g/L reducing sugar, 92.5% hydrolysis efficiency, 21.7% v/v ethanol, 0.401 L/kg yield, and 85.2% fermentation efficiency. Corn cobs produced 42.5 g/L reducing sugar, 68.0% hydrolysis efficiency, 16.2% v/v ethanol, 0.285 L/kg yield, and 78.5% fermentation efficiency. Quality tests showed that ethanol from corn cob had higher purity at 96.2% v/v with a clean blue flame, while sugarcane ethanol was 93.4% v/v with slight yellow flame tips indicating trace impurities. The feed stocks had acceptable acidity levels of 28–35 mg/L. Antibacterial assays at 70% v/v revealed ethanol from sugarcane completely inhibited Escherichia coli, whereas corn cob ethanol left a residual 19 CFU/mL despite higher purity. Sugarcane juice had higher fermentation efficiency and bioactivity as a first-generation feedstock, while corncobs offer a sustainable second-generation option with superior purity. Optimizing pretreatment, hydrolysis, and dehydration is essential to improve yield and consistency.