Parâmetros de hidrólise enzimática de farelo de arroz para produção de etanol de segunda geração

Abstract

The importance attached to biofuels has increased in recent years due to global concerns about the consequences of global warming advances and rising oil prices. However, the production of these conventional biofuels is faced with serious dif fi culties to achieve the desired levels because originate in general, plants that require extensive cultivation areas, limiting food production, which is a strong stimulus to the adoption of advanced technologies. Therefore, the current research indicate emerging technology as the production of fuel ethanol from biomass as an alternative to the use of renewable fuels. Thus, the production of ethyl alcohol from agricultural residues such as rice bran, presents as an alternative to transform the starch residue coproduct generating industry for the benefit of a clean industry. Therefore, the objective of this study was to evaluate the second-generation ethanol from rice bran, which is presented as a starchy source and an agricultural residue, giving the importance of adding value to this residue and contribute to the emerging research for second-generation ethanol. This was done by investigating the hydrolysis process of the defatted rice bran enzymatically applying a CCRD to evaluate the effect of process variables (concentration of the enzyme Alcalase, the ultrasound exposure time, and the frequency used in ultrasound) aiming process maximize the release of fermentable sugars for subsequent fermentation step. The highest concentrations of reducing sugars were achieved when using the frequency of 80 kHz in the ultrasonic bath, verifying that the CCRD variables showed no significant difference in response to 95% of significance, that is, the use of any values for both CCRD variables within the range studied, would not present difference in response, these considerations also observed for the percentage of ethanol response. Also confirmed the importance of the unrest in the breaking process of complex molecules, whereas the highest concentrations of reducing sugars were obtained by testing in different conditions of agitation.