Co-production of reducing sugars and xylo-oligosaccharides from rape straw through sodium dodecyl sulfate-mediated p-toluenesulfonic acid pretreatment

This research explored the efficacy of surfactant-mediated p-toluenesulfonic acid (p-TsOH) pretreatment for rape straw (RS) biomass fractionation toward improved enzymatic digestion. The effects of the type of surfactants [dodecyltrimethylammonium bromide (DTAB), sodium dodecyl sulfate (SDS), and Tween 80] on the pretreatment of p-TsOH were testified. Among them, anionic surfactant SDS rendered the best pretreatment effect. The pretreatment with SDS plus p-TsOH afforded effectual delignification (67.3 %+1.8 %) and xylan elimination (86.4+1.3 %), and the saccharification efficacy reached 81.5+1.2 %. In the pretreatment liquor, xylooligosaccharides (2.2 g/L) formed. Structural characterization of the pretreated RS implied effectual disruption of lignin-carbohydrate complexes, increased biomass porosity, weakened lignin surface area, declined ineffective adsorption of cellulases on lignin, and enhanced accessibility of cellulases to cellulose, contributing to improved enzymatic saccharification efficacy. Afterwards, the possible combination pretreatment mechanism was proposed. To sum up, this research afforded an effectual and eco-friendly approach for the refining of lignocellulose.