Sono-assisted enzymatic saccharification of sugarcane bagasse for bioethanol production

This study presents the sono-assisted pretreatment and enzymatic saccharification of sugarcane bagasse (SCB) for the production of bioethanol. The effect of sono-assisted alkali (NaOH) pretreatment on the removal of hemicellulose and lignin from SCB was studied and the results showed 80.8% of hemicellulose and 90.6% of lignin removal. Sono-assisted enzymatic saccharification was performed with Cellulomonas flavigena (MTCC 7450) and the yield was found to be affected by liquid-to-solid ratio (LSR), cell mass and pH. The optimum reaction time, LSR, cell mass and pH were found to be 360 min, 15:1, 15 g/L and 6.0 respectively. At optimum conditions, the maximum glucose yield obtained was 91.28% of the theoretical yield and the maximum amount of glucose obtained was 38.4 g/L. The enhancement in performance may be correlated with the swelling of cellulose and accelerated enzymatic saccharification due to the application of ultrasound. The hydrolyzate obtained was fermented using Zymomonas mobilis (MTCC 89) and about 91.22% of the theoretical ethanol yield was observed in 36 h of fermentation.

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► Sono-assisted alkaline pretreatment was carried out for effective lignin removal.
► C. flavigena was utilized for saccharification which is intensified using ultrasound.
► Optimization of sono-assisted saccharification was carried out.
► The data obtained at different conditions were analyzed using two fraction model.
► The suitability of the hydrolyzate obtained for fermentation was evaluated.