Efficient conversion of cornstalk to bioethanol using dilute H₂SO₄ pretreatment

Abstract: Corn stalk (CS) is one of the most abundant agricultural residues containing high polysaccharides for low-cost bioethanol production. In this study, dilute acid along with intensified thermal pretreatment of CS and other parameters were optimized for higher yield of bioethanol. CS samples were pretreated using H₂SO₄ concentrations of 0.5, 1.0, 1.5, 2.0, and 2.5% at 100 °C for 1 h reaction time. Optimal conditions of 2% acid-pretreated CS, 5% (w/v) of Saccharomyces cerevisiae addition and 48 h fermentation produced highest yield of bioethanol: 32.53 (g/L) which was 1.24-fold increase. Hemicellulose degradation of 75.68% was recorded in the 2% acid-treated substrate. Scanning electron microscope (SEM) images revealed induced porosity and surface area disruption of CS in the treated samples. Crystallinity of the treated samples increased as shown by X-ray diffraction (XRD) analysis. Low concentrated H₂SO₄ coupled with thermal pretreatment could be a viable method of lignocellulosic biomass utilization for efficient bioethanol production. Graphic abstract: [Figure not available: see fulltext.]