Ethanolysis of soybean oil catalyzed by magnetic CLEA of porcine pancreas lipase to produce ecodiesel. Efficient separation of ethyl esters and monoglycerides

Abstract

Porcine pancreas lipase (PPL, a 1,3-specific lipase) magnetic crosslinked enzyme aggregates have been used to produce Ecodiesel, a blend of fatty acid ethyl esters (FAEE) and acylglycerides (mainly monoacylglycerides, MAG), by ethanolysis of soybean oil. An Ecodiesel containing 67 wt% FAEE and 27.7 wt% acylglycerides was obtained using 750 tributyrin activity units (TBU) of PPL per gram of oil and an oil:ethanol molar ratio of 1:7 at 37 °C after 48 h of reaction. This product was fractioned into a FAEE-rich phase and a MAG-rich phase. To this goal, Soxhlet extractor and silica gel column chromatography were used. Soxhlet extraction for 60 cycles allowed recovering 91% of the ethylic esters fed into the extractor in a nonpolar phase containing around 90 wt% of FAEE, which could be further increased to around 92% by caustic or to 94% by enzymatic polishing treatments (using Lipozyme® CALB L), this product being close to the requirements of biodiesel. On the other hand, the separation in the silica gel column chromatography was more efficient to purify MAG, allowing the recovery of the 93% acylglycerides with emulsifying properties, with a final purity of 94 wt% MAG.