EVALUATION OF THE PRODUCTION OF OLIGOSACCHARIDES FROM A EUCALYPTUS SUBPRODUCT

Abstract

Lignocellulosic materials represent a source practically under-exploited, mainly in the area of biorefineries. Its use is mainly based on energy cogeneration (through oxidation), animal feed, production of charcoal, and cellulose. Lignocellulosic materials contain more than 60% cellulose and hemicellulose, and these fractions contain low energy efficiency and are an alternative for the production of higher added value products. Among many biotechnological applications, hemicellulose and cellulose can be used for the production of xylooligosaccharides (XOS) and glucooligosaccharides (GUS) for therapeutic and analytical purposes or in the form of monomers for the production of xylitol and/or ethanol. The quest for a healthy lifestyle through caring for food has boosted interest in functional foods. The experimental part of the project will involve the chemical characterization of a by-product of Eucalyptus (material obtained in the processing of wood chips). The pre-characterized by-product will be submitted to different hydrothermal pre-treatment operational conditions in order to obtain ideal conditions for XOS production. In addition, the by-product will be subjected to extraction steps of hemicellulose, which will also be chemically characterized. The previously extracted hemicellulose will be enzymatically hydrolyzed to evaluate the potential for XOS production. In addition, residues (rich in cellulose and lignin) obtained by hydrothermal pretreatment and extraction of the hemicellulosic fraction will be chemically characterized and hydrolyzed with commercial cellulases to evaluate the potential production of glucooligosaccharides (GUS). The XOS and GUS contain a high added value when compared to biofuels, cellulose and electric energy, being an alternative to be researched in the sectors of sugar-alcohol and cellulose. The proposed project intends to evaluate the production of XOS and GUS from a by-product of Eucalyptus by two different routes: hydrothermal pre-treatment and extraction and enzymatic hydrolysis of the hemicellulosic fraction by commercial xylanases. At the end of both processes of XOS production will be obtained a "residue" (rich in lignin and cellulose) that will be evaluated against the enzymatic hydrolysis with commercial cellulases aiming the production of GUS. In this way, the final residue obtained after cellulose hydrolysis (rich in lignin) can be used for cogeneration of energy. (AU)