Toward Full Poplar Utilization: Understanding of Coproducing Xylo-Oligosaccharides, Lignin, and Glucose through Citrate Buffer/Hydrophobic Organosols Biphasic Pretreatment

This is the authors' abstract. We don't add key points for this paper.

Biphasic pretreatment, incorporating water and immiscible organosol, presents a promising approach of one-step fractionation of hemicellulose, lignin, and cellulose in biomass. This work evaluated the simultaneous xylo-oligosaccharide (XOS) production alongside lignin isolation from poplar using various organosol (butanol, pentanol, 2-MeTHF, and MIBK) biphasic systems. The citrate buffer/organosol pretreatment was more favorable for XOS production than the biphasic system consisting of citric acid and organosol. Among the different citrate buffer/organosol systems, the citrate buffer/pentanol pretreatment demonstrated superior performance, achieving an extraordinary XOS yield of 40.5% and a lignin removal efficiency of 76.0% under optimized conditions (pH 2.7, 180 °C, 40 min, and 60% v/v), while preserving 91.6% of cellulose in residual poplar. The subsequent enzymatic hydrolysis of the treated residue resulted in a remarkable glucose conversion rate of 90.3%, significantly enhancing the bioconversion efficiency of poplar biomass. Furthermore, the recovered lignin retained structural integrity comparable to that of native lignin and exhibited high phenolic hydroxyl content, marking it as a valuable raw material for diverse applications. This study underscored the promise of a novel citrate buffer/pentanol biphasic pretreatment for the effective fractionation of biomass.