Ethanolysis of degummed soybean oil using magnetic CLEAs from Eversa® Transform

Abstract

Eversa^@ Transform magnetic crosslinked enzyme aggregates (Eversa-mCLEA) have been used to produce fatty acid ethyl esters (FAEEs) through the ethanolysis of soybean oil. Some variables influencing this reaction were studied using an experimental statistical design. After 12 hours of reaction, a maximum FAEEs yield of 64 wt% was obtained using 4 U_est/g oil of Eversa-mCLEA, an anhydrous ethanol/refined oil molar ratio of 11, and a temperature of 40°C. Degummed oil and hydrated ethanol were used as more cost-effective alternatives, leading to an increase in FAEEs yield (up to 73 wt%). The initial reaction rate increased with a lower molar ratio of hydrated ethanol/degummed oil; however, the final yield remained similar. The combined use of Eversa-mCLEA and Lipozyme 435 resulted in 86 wt% FAEEs and 4 wt% of free fatty acids (FFAs) after 24 hours. A caustic polishing step of the product yielded 90 wt% FAEEs and 0.17 wt% FFAs. These findings show that, using these substrates, a more effective purification step (such as fractional distillation) is required for the product to meet international standards for biodiesel commercialization.