A Review on Xylooligosaccharides Production From Lignocellulosic Biomass: Strategies, Applications, and Challenges

Biorefinery strategies that convert renewable lignocellulosic biomass into high-value xylooligosaccharides (XOS) are of great significance for reducing dependence on fossil resources and advancing sustainable biomass utilization. In recent years, the efficient production of XOS has attracted increasing attention because of its broad applications in food, feed, and health-related sectors. With the rapid development of XOS production technologies, a timely and critical overview of recent progress is needed. This review comprehensively summarizes the current progress in XOS production from lignocellulosic biomass, focusing on feedstock selection, production strategies, purification technologies, applications of XOS, and machine learning-assisted process optimization. The one-step organic acid hydrolysis is a promising XOS production strategy because of its operational simplicity, effective conversion yield, relatively mild reaction conditions, lower corrosion risk, and potential to enable the coproduction of multiple value-added products in biomass biorefineries. Deep eutectic solvent (DES) pretreatment strategies are also promising approaches for XOS production. In addition, the major challenges associated with industrial-scale XOS production are discussed, particularly in relation to the development of low-cost enzyme systems, efficient byproduct utilization, machine learning-assisted prediction and optimization of production parameters, and process integration. Overall, this review provides an updated perspective for the sustainable, efficient, and industrially relevant production of XOS.