Synthesis of butyl esters via ultrasound-assisted transesterification of macaúba (Acrocomia aculeata) acid oil using a biomass-derived fermented solid as biocatalyst

Abstract

Enzymatic synthesis of fatty acid esters from macaúba (Acrocomia aculeata) acid oil was studied in a solvent-free system using a fermented and dry babassu (Orbygnia oleifera) cake with lipase activity from Rhizomucor miehei, named solid enzymatic preparation (SEP). The reactions were carried out under the influence of ultrasound irradiation and using different alcohols. Higher ester yields were obtained using butanol as acyl acceptor. An experimental design was used to evaluate the effects of SEP concentration (2–12Ug−1 based on oil mass), butanol to oil molar ratio (3:1–12:1) and amount of water (0–10% based on oil mass) on the reaction yield. Fatty acid butyl ester (FABE) content around 80% was achieved after 70h with a substrate molar ratio of 5.47:1, water content of 10% as oil mass and amount of biocatalyst of 12Ug−1 as oil mass, at 40°C. It was possible to obtain high yields using a low-cost biocatalyst, produced using an agricultural waste, and low-cost raw-material, making biocatalytic route competitive compared to chemical route.