Ten kinds of lipases were examined as biocatalysts for the incorporation of short-chain fatty acids (acetic, propionic, and butyric acids) into triolein in order to produce one kind of reduced-calorie structured lipids. Trans-esterification (acidolysis) was successfully done in n-hexane by several microbial lipases. Among them, lipase from Aspergillus oryzae was used to investigate the effects of incubation time, substrate molar ratio, and water content on acidolysis. Finally, more than 80% of triolein was incorporated by butyric acid (molar ratio of triolein to butyric acid, 1:10) in the dried n-hexane at 52 degrees C for 72 h. More than 90% of the products was monosubstituent, which was esterified with this short chain fatty acid at the 1-position of the glycerol moiety of triolein. These results suggest that A. oryzae lipase would be a powerful biocatalyst for the synthesis of low caloric oil, such as triacylglycerol containing a mixture of long- and short-chain aliphatic acids.
Aspergillus oryzae Catalysis