Production of Ethyl Biodiesel from Macauba (Acrocomia aculeata) oil using commercial enzyme from Aspergillus oryzae (Eversa 2.0)

Production of vegetable oils biodiesel has presented more relevance due to efforts to reduce carbon footprints. Production of this biofuel as alternative to fossil fuels, and their use in addition to fossil diesel (as a public policy) is considered a mean to reduce the dependence on non-renewable sources and pollution in Brazil. Biodiesel production from Macauba pulp oil was explored in this work using enzymatic esterification (lipase of Aspergillus oryzae) and ethanol. Two oil quality conditions were investigated: crude and deacidified oil (20 % and 1.3 % acidity, approximately). For both conditions, temperature was maintained at 40°C, oil: ethanol ratio at 1.5 ethanol equivalent (according to transesterification stoichiometry), 3.4% lipase and 2.5% water. Reaction was performed at constant mechanical agitation. The complete reaction kinetics was determined, samples analysed at each time, up to 30h, by composition of triacylglycerols (TAG), mono- (MAG) and diacylglycerols (DAG), ethyl ester (FAEE) and free fatty acid (FFA) by liquid chromatography. For crude oil, TAG composition decreased almost to zero after 7h, and partial acylglycerols remained up to 24h. FAEE presented a significant increase after 3h. For deacidified oil, TAG decreased almost to zero up to 6h and FAEE significantly increased after 2h. In both oils a conversion higher than 90 % were observed. Results showed the enzyme ability of converting Macauba oil with high acidity in biodiesel, a viable alternative for once discardable vegetable oil with low market price value, becoming a more valued product with ecological and energy generation importance. This is quite significant in case of Macauba, considering that it is an endemic palm tree in national territory that has been used for reforestation of degraded areas in Minas Gerais and Para states. Also, use of ethanol instead of methanol (most used alcohol for biodiesel production) can improve the sustainability of this biofuel.