The Concentration and Purification of Xylan-Based Hemicelluloses

Abstract

In lignocellulosic biorefining, pretreatment plays a fundamental role in the optimal processing of the three main components of plant cell walls (cellulose, hemicelluloses, and lignin) for the subsequent production of chemicals and/or biofuels. Following pretreatment, concentration and/or purification methods are needed to facilitate more efficient production.Purification methods, such as enzymatic hydrolysis or glucose fermentation inhibitor removal, are generally used to separate the cellulose fraction; hence, purification processes are often synonymous with detoxification processes. Considerable research has examined the separation of specific components from kraft or sulphite pulp mill liquors.This chapter discusses xylan and derivative applications, particularly emphasising the separation and concentration of liquid streams containing hemicelluloses. The most frequently used technologies for hemicellulose purification from lignocellulosic biomass are antisolvent precipitation, solvent extraction (liquid–liquid extraction (LLE)), exchange or adsorption resins, and micro-, ultra-, and nanofiltration (MF, UF, and MF) membranes. These methods have been exhaustively reviewed, and this chapter considers many of them, focusing specifically on the yields and characteristics of hemicellulose streams.