Pré-tratamento e hidrólise do capim-elefante (Pennisetum purpureum) para obtenção de açúcares fermentescíveis

Abstract

With global warming, due to the emission of greenhouse gases, mainly CO2 generated in the burning of fossil fuels, global policies have pointed to the need to produce biofuel. A new alternative source of raw material for ethanol production is elephant grass (Pennisetum purpureum), which is a large grass, easy to handle and cultivate and abundant throughout Brazil. The objective of this work was to test different methods of pre-treatment of the elephant grass aiming the later enzymatic hydrolysis of the same. In addition, it aimed at the mathematical modeling of hydrolysis. The pretreatment methods tested were alkaline with NaOH, or with hydrogen peroxide or with chemical reaction of Fenton. The best pre-treatment result was obtained from the Fenton reaction in which 53.80% of cellulose and 10.00% of lignin were obtained. Enzymatic hydrolysis of the pretreated Fenton grass was carried out using the commercial enzyme Celluclast® 1.5L, where the best yield (17.39%) was obtained with 20 g L-1 of enzyme in 72 hours and higher productivity (2.51 g L-1 h-1) observed in 2 h. It was possible to adjust the mathematical models proposed in the process of enzymatic hydrolysis of elephant grass with the obtainment of fermentable reducing sugars. It was observed that, for higher concentrations of enzyme, the proposed mathematical model wich better adjusts the experimental results reached a coefficient of determination of R2 = 0.974 using the commercial enzyme.