Agronomic residues valorisation: potential applications for oligosaccharide production.

In last years, strong attention has been devoted to the utilization of agronomic residues, currently termed "lignocellulosic biomass". This feedstock is very attractive because it is renewable and not in competition with food sources. The exploitation of lignocellulosic biomass is expected to produce a double beneficial effect: 1) the elimination of waste that represent a source of pollution; 2) the production of useful by-products. Oligosaccharides that are non-digestible (NDOs) have important physiological properties beneficial to the health and are declared to behave as prebiotics. They can also be employed in feed, in products for diabetics, and in cosmetics as stabilizers1. Until now, fructo-oligosaccharides have been the main functional ingredients used but, however, some other classes of NDOs, such as xylo-oligosaccharides (XOS), are also emerging since they are moderately sweet, and have organoleptic characteristics suitable for incorporation into foods. Moreover, cello-oligosaccharides (COS) are also expected to possess prebiotic potential2. XOS and COS could be produced at industrial scale by processing residual vegetable biomass rich in cellulose and xylan. Here, we report on data about the enzymatic production of XOS and COS from lignocellulosic waste of different origin. Brewer's spent grain and chestnut shell, selected as raw materials, were subjected to enzymatic degradation by thermophilic enzymes isolated in our lab or by a blend of commercial enzymes. The final hydrolysis reaction mixtures contained oligosaccharides with different degree of polymerization.