Dilute ammonia pretreatment of sugarcane bagasse followed by enzymatic hydrolysis to sugars

In this work, dilute ammonia pretreatment was performed to break the intricate structure of sugarcane bagasse, which resists the enzyme accessibility to cellulose. The effects of pretreatment temperatures (140–180 °C), times (20–100 min) and ammonia dosage (5–25 wt%) on the recoveries of glucan, xylan, and acid in-soluble lignin were evaluated. The pretreatment performed at 170 °C, 60 min and 15 wt% ammonia resulted in delignification of 36.9 % and retaining 94.7 % of glucan and 63.1 % of xylan in the raw material. Then the enzymatic digestibilities of pretreated samples were investigated, 34.2 g glucose and 13.2 g xylose based on 100 g raw material could be obtained after that pretreatment condition, representing 82.7 % glucose and 47.3 % xylose in sugarcane bagasse. The enhanced digestibilities of dilute ammonia pretreated sugarcane bagasse were due to delignification and the removal of proportion of hemicellulose, which were confirmed by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis.