Revisão bibliográfica dos processos de pré-tratamento e hidrólise do bagaço de cana-de-açúcar para obtenção de etanol de segunda geração

Abstract

Second-generation ethanol (2G) or cellulosic ethanol is produced from waste from the sugar-energy industries. As an example of this residue is sugarcane bagasse. This technology allows reducing the use of non-renewable sources, being an alternative biofuel aimed at economic, environmental and social development. The process for obtaining 2G ethanol has two main steps that differ in processing compared to first-generation ethanol: acid pre-treatment and enzymatic hydrolysis. The acid pre-treatment of sugarcane bagasse aims to remove the barriers that prevent the enzymatic hydrolysis and fermentation of the polysaccharides present in the raw material, in addition to releasing the cellulose and hemicellulose molecules. Enzymatic hydrolysis is the process in which cellulolytic enzymes are added to the treated raw material to break the bonds of cellulose and hemicellulose polysaccharides into simple sugars, such as glucose and xylose, in order to make fermentation possible to generate ethanol from second generation. Thus, this work aims to understand the importance of these two main stages of the 2G ethanol process and what are the main techniques, advantages and disadvantages of obtaining them in a process in relation to other stages for obtaining glucose and xylose, thus bringing a broad view and understanding of the motivations for which sugar-energy plants have sought these alternatives in terms of the production sector of second-generation ethanol on a commercial scale.