A new selective separation strategy of eucalyptus hemicelluloses with the synergistic effect of hydroxyl and ketone groups in kojic acid pretreatment

In this study, eucalyptus hemicellulose was separated using kojic acid (KA), which contains hydroxyl and ketone groups. The maximum selectivity and hemicellulose separation yield were obtained (KA concentration of 10 %, 160 °C, and 50 min). The xylose separation increased from 79.36 ± 2.93 % to 84.36 ± 2.95 % after the KA pretreatment. The lignin separation decreased by 9.56 ± 0.06 % and 4.81 ± 0.26 % compared with acetic acid (AA) and salicylic acid (SA) pretreatment. It had the lowest condensed and highest noncondensed phenolic hydroxyl contents. The depolymerization and condensation of lignin were inhibited by the ketone group in KA. A synergistic effect of the hydroxyl acid and ketone groups on the efficient and selective separation of hemicellulose was discovered. This study provides a new approach for pretreating hemicellulose using novel multifunctional organic acids. • The efficient separation of eucalyptus by kojic acid pretreatment was discovered. • The xylose separation increased from 79.36 % to 84.36 %. • The lignin separation decreased by 9.56 % compared with acetic acid pretreatment. • The total hydroxyl content of lignin increased by 53.16 %. • The synergistic effect of hydroxyl acid and ketone group was discovered.