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

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.

Synthesis of ß-Galactooligosaccharides from Lactose Using Microbial ß-Galactosidases.

Galactooligosaccharides (GOSs) are nondigestible oligosaccharides and are comprised of 2 to 20 molecules of galactose and 1 molecule of glucose. They are recognized as important prebiotics for their stimulation of the proliferation of intestinal lactic acid bacteria and bifidobacteria. Therefore, they beneficially affect the host by selectively stimulating the growth and/or activity of a limited number of gastrointestinal microbes (probiotics) that confer health benefits. Prebiotics and probiotics have only recently been recognized as contributors to human health. A GOS can be produced by a series of enzymatic reactions catalyzed by ß-galactosidase, where the glycosyl group of one or more D-galactosyl units is transferred onto the D-galactose moiety of lactose, in a process known as transgalactosylation. Microbes can be used as a source for the ß-galactosidase enzyme or as agents to produce GOS molecules. Commercial ß-galactosidase enzymes also do have a great potential for their use in GOS synthesis. These transgalactosyl reactions, which could find useful application in the dairy as well as the larger food industry, have not been fully exploited. A better understanding of the enzyme reaction as well as improved analytical techniques for GOS measurements are important in achieving this worthwhile objective.