Valorization of Corncob through Integrated Acid and Enzymatic Pre-Treatment for Maximization Yield of Fermentable Sugar

The valorization of agricultural residues such as corncobs for bioethanol production offers a sustainable solution to global energy demands and environmental concerns. Present study focused on maximizing fermentable sugar yields from corncobs through an integrated acid and enzymatic pre-treatment process. Corncobs, which are abundant and rich in cellulose, were subjected to dilute sulfuric acid pre-treatment followed by enzymatic hydrolysis. A response surface methodology (RSM) using a Box-Behnken design was employed to optimize the pre-treatment process parameters acid concentration, temperature, and residence time. The obtained results revealed that optimal conditions for pre-treatment involved a 0.5% sulfuric acid concentration, a reaction temperature of 120 degrees C, and duration of 40 min. Under these conditions, the cellulose content of the pre-treated corncob increased to 66.10%, while the hemicellulose content significantly decreased. The enzymatic hydrolysis of pre-treated biomass resulted in a maximum saccharification yield of 41.1%, corresponding to a sugar yield of 185 mg/g of corncob. The study also includes the thermogravimetric analysis of raw corncob and BET surface area analysis that assessed thermal behaviour and the creation of pore space due to pre-treatment for improving enzyme accessibility. The findings highlighted that combining acid and enzymatic pre-treatment enhanced corncob into fermentable sugar. Aside from providing an efficient method of producing bioethanol, this process also contributes to the management of agricultural crop residue in a sustainable manner.