Comparative Study of Sulfuric Acid and Cellulase Enzymatic Hydrolysis of Cassava Stem Cellulose for Bioethanol Production

Abstract

Bioethanol production from lignocellulosic biomass is influenced by the effectiveness of the hydrolysis process in producing fermentable sugars. This study aimed to compare the effects of acid hydrolysis and enzymatic hydrolysis on glucose conversion and bioethanol content produced from cassava stems. Acid hydrolysis was carried out using H2SO4 at concentrations of 1 M, 2 M, and 3 M, while enzymatic hydrolysis used varying enzyme dosages of 1 g, 2 g, and 3 g. The hydrolyzed sugars were fermented with Saccharomyces cerevisiae, and the bioethanol was separated by distillation and analyzed for its composition. All experiments were conducted in triplicate, and data were analyzed using Welch's independent t-test. The results showed that enzymatic hydrolysis produced higher glucose concentration and glucose conversion after fermentation than acid hydrolysis. However, acid hydrolysis produced a significantly higher bioethanol content (78–90±2%) than enzymatic hydrolysis (10–28±1%) (p = 0.002). These findings indicate that under the operating conditions used, acid hydrolysis is more effective at producing bioethanol, whereas enzymatic hydrolysis is more effective at producing fermentable sugars. This study concluded that the hydrolysis method influences glucose conversion and bioethanol yield. Further research is needed to optimize enzymatic hydrolysis, fermentation, and distillation conditions and evaluate the combination of acid pretreatment and enzymatic hydrolysis to increase bioethanol production.