Enzymatic glycerolysis of a triglyceride in aqueous and nonaqueous microemulsions

Enzymatic solvolysis of a model triglyceride, palm oil, was performed in microemulsions containing isooctane, sodiumbis(2-ethylhexyl)sulfosuccinate (AOT), palm oil and a combination of water and glycerol as the polar component. Using a 1,3-specific lipase both hydrolysis, leading to the formation of fatty acid and one mole of monoglyceride, and glycerolysis, giving three moles of monoglyceride, occur. The reaction was very slow in a completely nonaqueous system. Addition of a small amount of water led to an increased rate of glycerolysis, in addition to hydrolysis. It was found that by using³H labelled material reaction products originating from the two reactions were formed in equimolar amounts. The products probably emanate from a common intermediate. The molar ratio, R, of water and glycerol to surfactant turned out to be critical, optimum R-value being 3.4. Four different lipases, one from porcine pancreas and three of fungal origin, were tested. No marked differences in ratio of monoglyceride to fatty acid formed were obtained, indicating that the ratio between glycerolysis and hydrolysis is constant regardless of the lipase used.