Abstract: The synthetic reaction of phosphatidyserine from soybean lecithin catalyzed by immobilized phospholipase D was carried out in oil-water two phase system, with PC and L-serine rich in oil and water phase, respectively. However, the by-product choline restrains the enzyme-catalyzed reaction rate and should be removed in time. In order to solve this problem, we adopted the repeated batch reaction. Increasing the substrate (PC) concentration decreased the yield of PS greatly. When various concentrations of choline chloride were added into the reaction mixture at low PC concentrations, there was a significant decrease in transphosphatidylation rate and the yield of PS. The using of repeated batch reaction was examined at high PC concentration to remove choline, the transphosphatidylation rate increased by 38%, and PS yield was 67%. The paper reported that the repeated batch operation is a novel technology for the synthesis of phosphlipid and increased the productivity of PS significantly. And the immobilized enzyme activity remained 58% after ten batches and nano-SiO₂-immobilized-PLD was suitable for repeated batch reaction.

Key words: phosphatidyserine, immobilized phospholipase D, repeated batch reaction, choline

摘要： 磷脂酶D(PLD)催化大豆磷脂合成磷脂酰丝氨酸(PS)反应是在油-水两相体系中进行的,大豆磷脂(PC)溶于有机相中,L-丝氨酸溶于水相中,但反应过程中产生副产物——胆碱,抑制酶的催化反应速率,需及时移除胆碱.本文主要采用反复分批式反应来解决这一问题.并考察了增大底物PC的浓度,PS的收率大大降低.低底物PC浓度下,添加不同浓度胆碱,转酯速率及PS收率都降低;高底物PC浓度下,采用反复分批式反应去除胆碱,转酯反应速率提高38%,PS收率达67%.研究表明反复分批式操作是一种生产磷脂的新型工艺,其中PS的生产能力明显提高,而且重复10次反应后,固定化酶活力仍保持58%,纳米SiO₂固定化磷脂酶D较好地适用于反复分批式反应.

关键词: 磷脂酰丝氨酸, 固定化磷脂酶D, 反复分批式反应, 胆碱