TRANSESTERIFICATION OF PHOSPHOLIPIDS IN DIFFERENT REACTION CONDITIONS

Transesterification of synthetic dimyristoyl phosphatidylcholine with oleic acid by commercial lipase preparations from Aspergillus niger an d Rhizomucor miehei was studied in the presence and absence of solvent . A high-performance liquid chromatography method for determination of the modified phosphatidylcholine was developed. Under solvent-free co nditions, transesterification could be carried out as efficiently as i n toluene, and the degree of hydrolysis was lower than in toluene. Tra nsesterification was influenced by the water content as well as by the fatty acid concentration in the reaction mixture. The optimum water c ontent for transesterification in solvent-free reaction medium was hig her than in toluene with both lipases, The yield of modified phosphati dylcholine increased, and the degree of hydrolysis decreased with incr easing fatty acid concentration. The maximum yield of modified phospha tidylcholine, 35% of the original phospholipid, was obtained with R. m iehei lipase.