Optimization of Glucose Production from Waste Office Paper by Sulfuric Acid Hydrolysis Using Response Surface Methodology (RSM)

Abstract

The depletion of conventional energy resources has increased global interest in renewable and sustainable biofuels. Wastepaper is a major biodegradable component of municipal solid waste and a promising feedstock for bioethanol production because of its high cellulose content. This study aimed to optimize glucose production from waste office paper through concentrated sulfuric acid hydrolysis using Response Surface Methodology (RSM) based on a Central Composite Design (CCD). Waste office paper was pretreated and hydrolyzed to evaluate the effects of acid concentration, acid loading, and reaction temperature, while the hydrolysis time was fixed at 3 h. The experimental results were used to develop a quadratic regression model, which adequately described the relationship between the process variables and glucose yield. The optimized hydrolysis conditions resulted in improved glucose production from wastepaper, demonstrating the feasibility of concentrated acid hydrolysis as an effective pretreatment method. The highest sugar concentration (16.00 g/L) was obtained at 30% sulfuric acid concentration, 175 mL acid loading, and 100°C after 3 h of hydrolysis. The developed model showed statistically significant results (p<0.0001) with a high coefficient of determination (R² = 0.987) and adjusted R² of 0.969, indicating good agreement between the predicted and experimental values. The glucose-rich hydrolysate can subsequently be fermented using Saccharomyces cerevisiae for bioethanol production. These findings indicate that waste paper is a promising renewable resource for sustainable biofuel production while contributing to waste minimization and environmental protection. Furthermore, the properties of the produced glucose were found to agree with Sudan’s standard specification for glucose. The novelty of this study lies in systematically optimizing concentrated sulfuric acid hydrolysis of waste office paper using RSM to maximize glucose production, thereby improving the potential ethanol yield during subsequent fermentation.