Pretreatment of sugarcane bagasse with NH4OH–H2O2 and ionic liquid for efficient hydrolysis and bioethanol production

An efficient pretreatment method using NH4OH–H2O2 and ionic liquid (IL) was developed for the recovery of cellulose from sugarcane bagasse (SCB). The regenerated SCB from the combined pretreatment exhibited significantly enhanced enzymatic digestibility with an efficiency of 91.4% after 12 h of hydrolysis, which was 64% higher than the efficiency observed for the regenerated SCB after the individual NH4OH–H2O2 pretreatment. 1-Allyl-3-methylimidazolium chloride ([Amim]Cl) dissolved the cellulose from the NH4OH–H2O2–pretreated SCB, and the crystallinity index (CrI) detected by X-ray diffraction (XRD) was reduced by 42%. The recycled and fresh [Amim]Cl demonstrated the same performance on the pretreatment of SCB for the enhancement of enzymatic digestibility. The regenerated SCB was subsequently used in simultaneous saccharification and co-fermentation (SScF) for bioethanol production by cellulase and yeast. The pretreatment did not have a negative effect on bioethanol fermentation, and an ethanol yield of 0.42 g/g was achieved with a corresponding fermentation efficiency of 94.5%.