Total utilization of lignocellulosic biomass with xylooligosaccharides production priority: A review

Xylooligosaccharides (XOS) are prebiotic oligosaccharides made from xylose monomers linked by β-1,4-glycosidic bonds and can be obtained by processing lignocellulosic biomass (LCB). Research on XOS is growing rapidly and has received widespread attention. XOS is currently used in food, feed, medicine, and agriculture. This article provides an overview of XOS production strategies, purification methods, applications, and ideas for biorefineries producing XOS and other products. Among them, organic acid catalysis is a promising production strategy with high yields, low by-products, fast reaction rates, and environmental friendliness. Various xylanases, including essential and auxiliary enzymes, have been developed to produce XOS. The use of immobilized enzymes in the enzymatic hydrolysis process will help to reduce the production cost of XOS, and it can enhance the hydrolysis performance of the enzyme to a certain extent; therefore, the development of immobilized enzyme technology is particularly important for the production of XOS by enzymatic hydrolysis. Nowadays, the processing of LCB has evolved towards a more efficient and cleaner direction. There are fewer studies on biorefineries for the production of XOS, and this review also suggests some ideas for the production of biorefineries.