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1-ethyl-3-methylimidazolium acetate ([EMIM] AC) pretreatment at moderate temperatures (60 °C and 75 °C) was evaluated for improving hydrolysability of Chinese pennisetum, a leading candidate as an energy crop, for bioethanol production. The pretreatment caused slight carbohydrate and lignin loss but significantly changed the material physicochemical characters, such as crystallinity and surface structure. Both changes exhibited positive effects on improving the enzymatic digestibility of the Chinese pennisetum. It was observed that approximately 90% of the cellulose and 50% of the xylan in the Chinese pennisetum after pretreatment at 75 °C were converted to fermentable monosaccharides by the combined cellulases and endo-xylanase. The results suggested that Chinese pennisetum could be effectively pretreated with ([EMIM] AC) pretreatment at moderate temperatures, and the high hydrolysis yield of fermentable sugars from pretreated Chinese pennisetum could be achieved by the synergistic action of accessory xylanase in enzymatic hydrolysis by cellulases. [ABSTRACT FROM AUTHOR]

The effects of aqueous ammonia pretreatment on structural properties and hydrolysabilities of Chinese Pennisetum and Hybrid Pennisetum were investigated. Aqueous ammonia pretreatment increased cellulose crystallinities and hydrolysabilities of Chinese Pennisetum and Hybrid Pennisetum. Compared with Chinese Pennisetum, Hybrid Pennisetum showed better enzymatic digestibility. Xylanase supplementation was more effective than the increase of cellulase loadings in the hydrolysis of aqueous ammonia pretreated Chinese Pennisetum and Hybrid Pennisetum. After supplementation of 2 mg of xylanase/g dry matter to 5 FPU of cellulases/g dry matter, the hydrolysis yields of cellulose of aqueous ammonia pretreated Chinese Pennisetum and Hybrid Pennisetum were 92.3–95.4%, and the hydrolysis yields of xylan were 86.9–94.2%. High hydrolysability and low dosage of enzyme loadings together with the advantages of high yield and widely distribution demonstrated the potential of Chinese Pennisetum and Hybrid Pennisetum for the production of platform sugars. [ABSTRACT FROM AUTHOR]