SELECTIVE FRACTIONATION AND DEPOLYMERIZATION OF LIGNOCELLULOSIC BIOMASS USING SUBCRITICAL AND SUPERCRITICAL WATER TO PRODUCE HEMICELLULOSE, CELLULOSE AND LIGNIN

摘要

Cellulose and hemicelluloses contained in woody biomass can be hydrolysed to monomeric sugars, which can be fermented to ethanol, or can be converted into higher value products [1]. Hemicelluloses, when isolated from biomass, have unique properties. They can be used to produce films for packaging applications in substitution to synthetic plastics, as polysaccharides works as barriers against oxygen permeation; another important application is the production of aerogels to insulate products. Xylose from hemicellulose, for instance, can be converted to furfural, which is a precursor used in different fields, such as oil refining, plastics, pharmaceutical, and agrochemical industries. L-Xylose can be also hydrogenated or enzymatically transformed to xylitol, which is a sweetening agent and is also used for preventing tooth decay [2]. The idea of transforming biomass to energy, materials, and chemicals, defines the concept of biorefinery, particularly interesting topic nowadays, considering the issues related to fossil combustibles and derivatives [3-5].