Dry polishing of enzymatically produced fatty acid methyl esters through polymeric membranes

Abstract

Industrial production of enzymatic biodiesel is based on the use of low-quality feedstocks with usually high water and free fatty acid contents. For this reason, a polishing step is essential to remove impurities and meet the required quality for downstream processing, storage, or commercialization of the product. In this work, we propose the application of membrane separation to polish crude industrial enzymatic fatty acid methyl esters (FAME). Polymeric membranes of different features were selected and tested for crude industrial FAME filtration. Results showed that the 10 kDa ultrafiltration (UF) membrane provided the best performance resulting in the exemption of soap content in the permeate. Moreover, the UF membrane was successfully able to drastically reduce the color, total contamination, and phosphorus content of FAME samples. The permeate flux was found stable during the ultrafiltration process in crossflow mode and no severe fouling was observed, thus making the membrane separation process a promising approach for FAME polishing.