A combined pretreatment with ultrasound-assisted alkaline solution and aqueous deep eutectic solvent for enhancing delignification and enzymatic hydrolysis from oil palm fronds

Victor Zhenquan Ong, Ta Yeong Wu, Kylie Kai Li Chu, Wei Yao Sun, Katrina Pui Yee Shak

    Research output: Contribution to journalArticleResearch

    10 Citations (Scopus)


    Oil palm frond (OPF) is one of the most abundant lignocellulosic biomass wastes found in the palm oil industry. However, the recalcitrant nature of OPF makes it hard to produce reducing sugar and convert it into subsequent high-value chemicals. Therefore, OPF was subjected to an ultrasound-assisted NaOH-aqueous deep eutectic solvent (DES) pretreatment in this study to increase delignification and enhance enzymatic saccharification. The effects of ultrasonication on the combined NaOH-aqueous DES for OPF pretreatment and saccharification were scrutinized. Under the recommended ultrasonic pretreatment (amplitude 60 %, duration 30 min) with 2.5 % NaOH-aqueous DES, lignin removal was significantly improved to 47.00 % in comparison to that obtained without ultrasound pretreatment, 30.92 %. OPF subjected to the recommended pretreatment was able to retain a high polysaccharide content, where subsequent enzymatic saccharification was able to achieve a glucose yield of 90.12 %. Physical and chemical characterizations of pretreated OPF were carried out to provide evidence to explain the observed improvement in lignin removal and enzymatic hydrolysis. The use of NaOH-aqueous DES as an ultrasonic medium was proven to be an effective method to promote a novel one-pot, two-processes pretreatment system.

    Original languageEnglish
    Article number112974
    Number of pages11
    JournalIndustrial Crops and Products
    Publication statusPublished - Feb 2021


    • Biomass valorization
    • Biorefinery
    • Energy irradiation
    • Green solvent
    • Lignocellulosic biomass
    • Waste management

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