Microwave pretreatment of lignocellulosic material in cholinium ionic liquid for efficient enzymatic saccharification

•Microwave pretreatment of lignocellulose in cholinium ionic liquids is suggested.•Microwave pretreatment in cholinium ionic liquids was conducted at 110 °C for 20 min.•This was more efficient than the existing thermal pretreatment in cholinium ionic liquid.

We demonstrated that the enzymatic hydrolysis of cellulose after microwave pretreatment of lignocellulosic material in ionic liquids (ILs) is drastically enhanced compared with that after conventional thermal pretreatment in ILs. Three types of cholinium ILs, choline formate (ChFor), choline acetate (ChOAc), and choline propionate (ChPro), were examined. The cellulose saccharification percentage was approximately 20% for kenaf powders pretreated in ChFor, ChOAc, and ChPro by conventional heating at 110 °C for 20 min. In contrast, approximately 60–90% of cellulose was hydrolyzed to glucose after microwave pretreatment in the same ILs at 110 °C for 20 min.