Optimization of the organosolv process with glycerol in acid medium for the pretreatment of sugarcane bagasse aiming to enhance the enzymatic digestibility of the material to be used in ethanol production by fermentation

Abstract

In recent years, special attention has been given to the use of vegetal biomass as raw material for obtaining fuel ethanol by fermentation. The production of this compound from biomass agricultural or forestry residues or byproducts, has as advantage the large availability of this kind of material. However, there are additional difficulties due to the closed structure formed by the plant cell wall components, among which there are macromolecules of carbohydrate that must be hydrolyzed to release fermentable sugars necessary for fermentation process. This hydrolysis, more specifically in relation to the macromolecular fraction cellulose, has been carried out enzymatically. However, a pretreatment of the material is needed to increase the digestibility of cellulose by enzymes. Depending on the pretreatment, sugars from the macromolecular fraction hemicellulose can also be released, which are constituted mainly pentoses, which can be transformed into ethanol by specific microorganisms. The pretreatment more used is with dilute acid, which, however, requires conditions of high pressure and temperature. In this context, this project has as objective to evaluate the pretreatment of the sugarcane bagasse by organosolv process using glycerol in medium containing dilute sulfuric acid solution aiming to increase the enzymatic digestibility of the cellulosic material. The choice of this raw material is associated with its abundance in Brazil and it is intended that the use of glycerol contributes to reducing the severity of the process, in particular with the possibility of working at atmospheric pressure. (AU)