Deep eutectic solvent and inorganic salt pretreatment of lignocellulosic biomass for improving xylose recovery

• Main Authors: Loow, Yu-Loong, Wu, Ta Yeong, Yang, Ge Hoa, Ang, Lin Yang, New, Eng Kein, Siow, Lee Fong, Md. Jahim, Jamaliah, Mohammad, Abdul Wahab, Teoh, Wen Hui
• Format: Article
• Published: Elsevier 2018
• Subjects: TP Chemical technology
• Online Access: http://eprints.um.edu.my/21396/; https://doi.org/10.1016/j.biortech.2017.07.165

Deep eutectic solvents (DESs) have received considerable attention in recent years due to their low cost, low toxicity, and biodegradable properties. In this study, a sequential pretreatment comprising of a DES (choline chloride:urea in a ratio of 1:2) and divalent inorganic salt (CuCl 2 ) was evaluated, with the aim of recovering xylose from oil palm fronds (OPF). At a solid-to-liquid ratio of 1:10 (w/v), DES alone was ineffective in promoting xylose extraction from OPF. However, a combination of DES (120 °C, 4 h) and 0.4 mol/L of CuCl 2 (120 °C, 30 min) resulted in a pretreatment hydrolysate containing 14.76 g/L of xylose, remarkably yielding 25% more xylose than the CuCl 2 -only pretreatment (11.87 g/L). Characterization studies such as FE-SEM, BET, XRD, and FTIR confirmed the delignification of OPF when DES was implemented. Thus, the use of this integrated pretreatment system enabled xylose recoveries which were comparable with other traditional pretreatments.