The potential for oligosaccharide production from the hemicellulose fraction of biomasses through pretreatment processes: xylooligosaccharides (XOS), arabinooligosaccharides (AOS), and mannooligosaccharides (MOS)

Schematic hydrolysis of xylan to xylooligosaccharides and xylose by different enzymes. Hemicellulosic oligosaccharides are sugar molecules that contain xylose, mannose, and arabinose in variable concentrations ranging from 3 to 10 molecules. These medium and long chain sugars can be classified as non-digestible carbohydrates, thus playing an important role in gastrointestinal health as prebiotics. Their physiological benefits, primarily stimulation of the proliferation of lactic acid bacteria and bifidobacteria in the colon informs their significance as high value nutraceuticals in the food and pharmaceutical industry. In addition they are well known as useful components of important pharmaceutical products. There are two main ways of producing these sugars from biomass, which include enzymatic and non-enzymatic pretreatments. Each of the two processes has advantages and disadvantages. Enzymatic processes are associated with high costs, higher concentration of monomeric sugars, and low oligosaccharide yields while thermo-chemical processes are usually associated with undesirable byproducts such as furfural and lower oligosaccharide yields. In this paper we discuss the benefits and constraints for optimization of different methods for the production of oligosaccharides from biomass.