Cholinium ionic liquid/cosolvent pretreatment for enhancing enzymatic saccharification of sugarcane bagasse

• Sugarcane bagasse was pretreated with choline acetate and organic solvents.
• Combination uses of choline acetate and organic solvents were compared.
• Saccharification ratio was not changed until 50% organic solvent was added.

In order to reduce the amount of choline acetate ([Cho][OAc]), (a less expensive, more biodegradable and biocompatible ionic liquids) used in the pretreatment of sugarcane bagasse, [Cho][OAc] combined with organic solvents pretreatments were attempted. The glucose yields after a 72-h enzymatic saccharification of sugarcane bagasse pretreated with [Cho][OAc] combined with organic cosolvents dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), or ethylene glycol (EG) at a weight ratio of 1:1 keeping at 130 °C for 180 min were approximately equal to those from the bagasse treated with [Cho][OAc] alone. The result indicated that the combination use of the cosolvents made it possible to reduce 50% of amount used of [Cho][OAc]. The enhancement effect of the [Cho][OAc]/cosolvent pretreatment on enzymatic saccharification could be attributed to an equal or greater effect on removal of hemicelluloes and lignin compared to the [Cho][OAc] treatment alone, although a lower effect on reduction in cellulose: which was supported by componential and X-ray diffraction (XRD) analyses. The bagasse pretreated with [Cho][OAc]/DMSO (1:1 w/w) used in simultaneous saccharification and fermentation using Saccharomyces cerevisiae BA11, and ethanol was produced with a corresponding to conversion ratio of 69.9%.