An application of low concentration alkaline hydrogen peroxide at non-severe pretreatment conditions together with deep eutectic solvent to improve delignification of oil palm fronds

Cost-effective pretreatments are essential to overcome the recalcitrant properties of lignocellulosic biomass in order to reutilize cellulosic components within the biomass for value-added products. In this study, a sequential pretreatment of low concentration (< 1.00 vol%) alkaline hydrogen peroxide (AHP) at ambient temperature (similar to 25 degrees C) and pressure (1 atm.) with Type III deep eutectic solvent (DES) was used to fractionate oil palm fronds (OPF). A combination of AHP (0.25 vol%, 90 min) and DES (120 degrees C, 4 h) at the later stage resulted in a pretreated OPF with a delignification of 18.99%, remarkably improved DES-alone delignification extent by 1.6 folds. The characterizations of pretreated OPF confirmed that mild conditions AHP + DES pretreatment could synergically improve the delignification efficiency. Thus, the use of this sequential pretreatment enabled the lignin extraction and effectively disrupted the recalcitrant structure of OPF, yielding a potential feedstock for a biorefinery process at the later stage.