Lipase-catalyzed synthesis of lysophosphatidylcholine using organic cosolvent for in situ water activity control

Lysophosphatidylcholines (LPC) were synthesized from L-alpha-glycerophosphatidylcholine (GPC) by lipase-catalyzed esterification in a solvent-free system. Adding small amounts of a water-mimicking solvent such as dimethylformamide (DMF) to the reaction media significantly enhanced the reaction rate and the product yield. The role of solvent was studied with regard to changes in substrate solubility, the water activity of the reaction system, and the water content of the enzyme. Whereas the solubility of GPC was virtually unaffected by the addition of DMF at controlled water activity, it was considerably affected by water activity. DMF itself lowered the water activity of the system and deprived Lipozyme 1M of water. The LPC production was also controlled by varying the initial water content of the enzyme. When two kinds of controls were employed together, a synergistic effect was observed and a 90% conversion was achieved. As a result, an operating window was suggested for LPC production, including water activity of Lipozyme IM and concentration of DMF as two parameters.