固定化磷脂酰胆碱水相酶催化合成磷脂酰丝氨酸

本文构建了一种固定化底物磷脂酰胆碱(phosphatidylcholine,PC)水相催化体系,磷脂酶D转化PC合成磷脂酰丝氨酸(phosphatidylserine,PS)新技术。探讨了沉淀剂种类、载体类型和底物初始添加量等主要因素,对固定化底物PC过程中PC吸附率的影响,获得了最佳工艺参数。在此基础上,进一步研究了固定化底物PC酶法合成PS的时间反应动力学和酶重复利用特性。结果表明,催化反应24 h后,PS得率为98.74%,磷脂酶D重复使用10次,PS得率仍然大于60%。文章还比较了固定化底物水相催化体系和双液相催化体系酶法合成PS效果,结果发现,固定化底物水相催化体系中PS得率和酶循环利用特性均优于双液相催化体系。本文研究结果为今后酶法改性PC合成PS提供了一种新的催化反应体系。

Enzyme Catalytic Synthesis of Phosphatidylserine in Aqueous Phase through Immobilization of Phosphatidylcholine

This work reported a novel technology on bioconversion of phosphatidylcholine (PC) into phosphatidylserine (PS) by phospholipase D (PLD) in an aqueous phase catalytic system through immobilization of substrate phosphatidylcholine (PC). The major factors affecting PC adsorption efficiency were investigated to obtain the optimal parameters, such as the kinds of precipitant reagents, carrier types, and substrate loading concentration. Furthermore, the time kinetics of PS catalytic synthesis by PLD through immobilization of substrate PC and the recycling utilization of enzyme PLD were also examined. Results showed that the yield of PS achieved 98.74% after 24 h reaction, and PLD had an excellent recycling utilization. When it was reused for 10 batches, PLD could still yield more than 60% of PS. In the end, the efficiency of PS catalytic synthesis by PLD was also compared between through immobilization of substrate PC and in two-liquid phase system. It was found that higher yield of PS and more excellent stability of PLD were achieved through immobilization of substrate PC than in two-liquid phase system. These findings would provide a novel catalytic system for PC bioconversion into PS in the future.