P1: Lipase reutilization in the synthesis of acetylated monoacylglycerols

Monoacylglycerols are usually chemically synthesized, showing several inconveniences as low yield; use of high temperature, above 200°C; formation of undesirable compounds; and necessity of product purification through molecular distillation, a high cost process. Enzymatic synthesis is an alternative to reduce or eliminate such inconveniences as it is a specific reaction; requires lower processing temperatures, and simple vacuum distillation can be used for product purification. As an additional advantage, the lipase can be reused turning the process economically viable. In the present study, acetylated monoacylglycerides were produced by enzymatic interesterification of hydrogenated vegetable oil with triacetin (1:3 proportion) in the presence of 4% commercially available lipase, Lipozyme^® TL IM (Novozymes), 6 hours reaction time at 60°C, magnetically agitated, and under vacuum. Subsequent reactions up to 7 times were evaluated with the enzyme reused from the previous cycle, and up to 9 times with the addition of 10% fresh enzyme.  The yield of the reaction products, monoacyl-, diacyl- and triacylglycerols, was evaluated by HPSEC (High Performance Size Exclusion Chromatography) using 100A and 500A (300 mm x 7.8 mm JORDI Gel DVB) columns. The enzyme Lipozyme TL IM could be reused in the synthesis of acetylated monoacylglycerols up to 3 times with high yield, around 67%. With the addition of 10% fresh enzyme, it could be reused up to 6 times with a yield above 70%.