STUDIES ON LIPASE

The hydrolytic and esterifying actions of lipase have been studied using the crystalline electrophoretically homogeneous enzyme of Aspergillus niger. The enzyme hydrolyzed vegetable oils, triglycerides of long or short chain fatty acids, and alkyl esters of long chain fatty acids, but not alkyl esters of short chain fatty acids.The hydrolytic action was found to depend on the chain length of either fatty acid or alcohol moiety of the substrate, and the maximal activities were found with fatty acids of eight and sixteen carbons using single esters as the substrate.The enzyme catalyzed the synthesis of the glycerides and the single esters of fatty acids, and the activity seemed to be influenced by the structure of the substrate. The esterification of oleic acid with glycerol was achieved up to 60% when the concentration of water in the reaction mixture was kept as low as possible. The reversibility of the reaction, fatty acid+alcohol (including glycerol) † ester (including glyceride)+water, was confirmed by the fact that the changes in the concentration of free oleic acid formed (or consumed) during the reaction was related to those of water and glycerol contents in the reaction mixture.