LAUSR

Deep eutectic solvents (DESs) are new and rapid emerging green solvents that have been gaining much attention lately. In this work, DES was prepared by mixing choline chloride with lactic acid with the molar ratio of 1:10 to pretreat empty fruit bunches. The effects of pretreatment temperature, pretreatment time and solid-to-solvent ratio were investigated. A maximum reducing sugars yield of 51.1% was obtained at the operating conditions of 100 °C for 1 h with solid-to-solvent ratio of 1:10 (w/v). The reducing sugars yield obtained for DES pretreatment was higher than dilute acid, alkaline and organosolv pretreatment suggesting DES pretreatment is a promising alternative to conventional pretreatment techniques. Furthermore, there was no reducing sugar loss during DES pretreatment. The outstanding DES pretreatment performance was further confirmed by both Fourier-transform infrared spectroscopy and scanning electron microscopy indicated that DES pretreatment was effective in altering biomass structure by disrupting the hydrogen bonding interactions within the chains of cellulose molecules and lignin extraction.