Articles

As a renewable alternative to fossil fuels, the production of bioethanol and biochemicals from lignocellulosic biomass has drawn significant interest. For biochemical conversion, pretreatement is the most crucial step, which removes biomass recalcitrance to improve cellulose’s accessibility for enzymatic saccharification and fermentation. This study investigated the potential of dilute sulfuric acid pretreatment of waste rice straw to produce building-block sugars and bioethanol. The study focused on optimizing several key parameters, including dilute acid concentration (60 mM), pretreatment time (30 minutes), pretreatment temperature (120°C), and liquid-to-solid ratio (5:1). This study also compared the efficiency of dilute acid pretreatment of rice straw with conventional dilute alkali and organosolv pretreatment techniques. The results showed that dilute acid pretreatment effectively dissolved a significant amount of hemicellulose under these circumstances, retaining 97.96% of cellulose in the solid substrate, which led to 64.28% glucose yield in enzymatic saccharification. The rice straw structure underwent morphological changes (i.e., cell wall rupture and changes in crystallinity) as the result of acid pretreatment, which were confirmed using SEM and XRD techniques. Furthermore, Saccharomyces cerevisiae fermentation trials showed that the total bioethanol yield was 78.7% in simultaneous saccharification and fermentation, demonstrating the potential of optimized dilute acid pretreatment in the production of bioethanol from rice straw. This study provides important insights for developing a biorefinery for the effective valorization of rice straw and other agricultural waste biomasses.