Enzymatic synthesis of bio-based wax esters from palm and soybean fatty acids using crude lipases produced on agricultural residues

Abstract

The increased demand for the consumption of vegetable oils has led to the generation of high quantities of by-products, such as palm and soybean fatty acid distillates (PFAD, SFAD), as a result of the refining process. In this study PFAD and SFAD were used as raw materials for the enzymatic production of wax esters in a solvent-free system. A fungal crude lipase was produced by solid state fermentation using babassu cake as substrate and then fermented solids were used as biocatalyst for wax esters synthesis using cetyl and oleyl alcohols. The highest wax esters production of 80% was achieved for the SFAD-cetyl, SFAD-oleyl and PFAD-oleyl esters using 8.8 U/g of biocatalyst at 50 °C. The proposed biocatalysis could be economically feasible since the crude lipase was efficiently reused for up to five repeated batch reactions. The physicochemical properties of the wax esters were also studied. Differential scanning calorimetry and the determination of acid, iodine and saponification values showed that the wax esters have similar properties to natural waxes. This study demonstrated the valorization of by-products from vegetable oil production processes as an alternative feedstock for the synthesis of bio-based wax esters with potential use in food, cosmetics and chemical applications.