Extraction and modification of hemicellulose from lignocellulosic biomass: A review

Abstract

Hemicellulose is a carbohydrate biopolymer second only to cellulose, which is rich and has a broad application prospect. The limitation of high-value utilization of hemicellulose has been a long-standing challenge due to its complex and diversified structure. The extraction and subsequent modification of hemicellulose from lignocellulosic biomass represent a promising pathway toward this goal. Herein, the extraction processes including physical pretreatment, chemical pretreatment, and combined pretreatment for separating hemicellulose from lignocellulosic biomass were introduced, and the advantages and disadvantages of various extraction procedures were also described. The chemical modification of hemicellulose such as etherification, esterification, grafting, and cross-linking modification was reviewed in detail. The separation and modification of hemicellulose in the future are prospected based on the earlier studies.