Synthesis of CLA-Rich Lysophosphatidylcholine by Immobilized MAS1-H108A-Catalyzed Esterification: Effects of the Parameters and Monitoring of the Reaction Process

Abstract

Conjugated linoleic acid (CLA)-rich lysophosphatidylcholine (LPC) with many proven beneficial effects is successfully synthesized by an immobilized mutant lipase (MAS1-H108A)-catalyzed esterification of glycerophosphorylcholine (GPC) and CLA-rich FAs. Under the optimized conditions (temperature of 55 °C, substrate molar ratio of CLA-rich FAs to GPC of 40:1, and enzyme loading of 300 U g−1), LPC content as high as 89.10 mol.% is achieved, which is exceptionally higher than any ever-reported value. By monitoring the esterification process, it is found that sn1-LPC is easy to synthesize and is the predominant product, while sn2-LPC and phosphatidylcholine (PC) are difficult to synthesize and are with lower content in the final product. The formed sn2-LPC during esterification may mainly attribute to the acyl migration of sn1-LPC and the ratio of sn1-LPC to sn2-LPC finally plateaus at approximately 7. Besides, our results also demonstrate that sn2-LPC is the main template for the synthesis of PC. Finally, a complete reaction scheme for the synthesis of LPC by immobilized MAS1-H108A-catalyzed esterification of GPC and fatty acids is mapped out. Overall, the highest LPC content can be obtained by immobilized MAS1-H108A-catalyzed esterification and there is the first study for systematical studying the reaction process of CLA-rich LPC synthesis. Practical Applications: Previous studies have demonstrated that Novozym 435 is the most suitable catalyst for the synthesis of CLA-rich LPC. However, the LPC content obtained by Novozym 435 is only 70 mol.% and the reaction process for the synthesis of CLA-rich LPC has not been studied systematically, which restricts the commercial production of CLA-rich LPC in some extent. Therefore, further exploration of alternative enzyme resources for highly efficient synthesis of CLA-rich LPC and trying to clarify the reaction process of CLA-rich LPC synthesis are of significant importance for the future commercially industrial production of CLA-rich LPC. A complete reaction scheme for the synthesis of LPC using GPC and FAs as substrates by immobilized MAS1-H108A-catalyzed esterification. CLA-rich FAs are used as model FAs in this study. Reaction parameters, such as temperature, CLA-rich FAs/GPC ratio, and enzyme loading are selected to study their effects on the esterification. Concurrently, the reaction process is monitored. LPC content as high as 89.10 mol.% is obtained, which is the highest reported value thus far for the synthesis of CLA-rich LPC. Finally, the reaction scheme for the synthesis of LPC by immobilized MAS1-H108A-catalyzed esterification is mapped out.