Produção de etanol de segunda geração a partir de resíduos industriais da jabuticaba utilizando líquidos Iônicos para a quebra da celulose

Abstract

Biofuels are defined as fuels synthesized through renewable resources, including second generation ethanol. These are obtained from the breakdown of cellulose and presents itself as an alternative to the environmental crisis by using industrial residues such as jabuticaba bark as raw material. This process is based on the accomplishment of a pretreatment of cellulose, in this case using ionic liquids (LIs). For the performance of the tests one LI was synthesized, the triethylammonium hydrogen sulfate and the other commercially acquired, methylimidazole hydrogen sulfate. After that, pretreatments were performed, varying the LIs, for the pulp breaking of the bark of the jabuticaba. Fermentation for ethanol production was performed in four different conditions for comparison, with stirring throughout the 7 day fermentation period, experiment A, with temperature control throughout the 5 day fermentation period, experiment B, with stirring at and temperature control throughout the 5-day fermentation period, experiment C, and with addition of sugar and temperature control throughout the 5-day fermentation period, experiment D. The fermentative must was then distilled for ethanol purification, it was observed that jabuticaba contains a high sugar content in its shell and that methylimidazole hydrogen sulphate obtained better performance when compared to triethylammonium hydrogen sulphate on cellulose breakage due to fermentation conditions such as pH and temperature. In addition, significant efficiency can be observed by adding agitation at the beginning of the process, as well as the addition of metabisulphite to the control of microorganisms that could compete with Saccharomyces cerevisiae, so that it was possible to obtain 62.66% of ethanol in experiment D, 41.25% in experiment C and 15.37% in experiment B. Therefore, the production of ethanol from industrial residues of jabuticaba can be a viable process, after performing tests for optimization of the process.