Lipase-catalyzed alcoholysis of sunflower oil under anhydrous conditions was examined. Lipases from
Pseudomonas fluorescens and 2 immobilized enzymes from
Mucor miehei and a
Candida sp. gave sufficient conversion with petroleum ether as the solvent, even when methanol and ethanol were used. The overall content
of tri-, di- and monoglycerides, as well as the corresponding alkyl esters, was measured. Because
Pseudomonas lipase led to almost quantitative esterification, further studies were carried out with that enzyme varying the amounts of
enzyme or the alcohols. Acceptable conversions were achieved even without solvent. Reaction rates of alcoholysis with 5 homologous
alcohols, with or without the addition of water, were measured, and in all cases the reaction rates increased with higher
chain length of the alcohol. In the case of methanol the highest rate was obtained without any addition of water, but a significantly
higher rate was observed with 96% ethanol as opposed to absolute ethanol. The main advantages of lipasecatalyzed, nonaqueous
alcoholysis as compared to classical procedures are the mild reaction conditions, the isolation of glycerin without further
purification and without the formation of chemical waste, and the ability of lipases to catalyze the esterification of free
fatty acids.