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

Yu Loong Loow, Ta Yeong Wu, Ge Hoa Yang, Lin Yang Ang, Eng Kein New, Lee Fong Siow, Jamaliah Md. Jahim, Abdul Wahab Mohammad, Wen Hui Teoh

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114 Citations (Scopus)


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 (CuCl2) 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 CuCl2 (120 °C, 30 min) resulted in a pretreatment hydrolysate containing 14.76 g/L of xylose, remarkably yielding 25% more xylose than the CuCl2-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.

Original languageEnglish
Pages (from-to)818-825
Number of pages8
JournalBioresource Technology
Publication statusPublished - Feb 2018


  • Biomass valorization
  • Biorefinery
  • Green solvent
  • Hemicellulose
  • Lignin
  • Oil palm fronds

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