Transesterification Of Phosphatidylcholine Research Articles

Transesterification of phosphatidylcholine with DHA-rich algal oil using immobilized Candida antarctica lipase B to produce DHA-phosphatidylcholine

Docosahexaenoic acid (DHA) enriched with phospholipids (PLs) (DHA-PLs) is a type of structured PL with good physicochemical and nutritional properties. Compared to PLs and DHA, DHA-PLs has higher bioavailability and structural stability and many nutritional benefits. To improve the enzymatic synthesis of DHA-PLs, this study investigated the preparation of phosphatidylcholine (PC) enriched with DHA (DHA-PC) via enzymatic transesterification of algal oil, which is rich in DHA-triglycerides, using immobilized Candida antarctica lipase B (CALB). The optimized reaction system incorporated 31.2% DHA into the acyl chain of PC and converted 43.6% PC to DHA-PC within 72 h at 50 °C, 1:8 PC: algal oil mass ratio, 25% enzyme load (based on total substrate mass), and 0.02 g/mL molecular sieve concentration. Consequently, the side reactions of PC hydrolysis were effectively suppressed and products with high PC content (74.8%) were produced. Molecular structure analysis showed that exogenous DHA was specifically incorporated into the sn-1 site of the PC by immobilized CALB. Furthermore, the evaluation of reusability with eight cycles showed that the immobilized CALB had good operational stability in the present reaction system. Collectively, this study demonstrated the applicability of immobilized CALB as a biocatalyst for synthesizing DHA-PC and provided an improved enzyme-catalyzed method for future DHA-PL synthesis.

Green biosynthesis of rare DHA-phospholipids by lipase-catalyzed transesterification with edible algal oil in solvent-free system and catalytic mechanism study.

Docosahexaenoic acid (DHA)-enriched phosphatidylcholine (PC) has received significant scientific attention due to the health benefits in food and pharmaceutical products. In this work, the edible algal oil rich in DHA-triacylglycerol (DHA-TAG) without pretreatment was first used as the DHA donor for the transesterification of phospholipids (PLs) to prepare three kinds of rare PLs, including DHA-PC, DHA-phosphatidylethanolamine (DHA-PE), and DHA-phosphatidylserine (DHA-PS). Here, 153 protein structures of triacylglycerol lipase (EC 3.1.1.3) were virtually screened and evaluated by transesterification. PLA1 was the best candidate due to a higher DHA incorporation. Results showed that the transesterification of PC with DHA-TAG at 45°C and 0.7% water content (without additional water addition) could produce DHA-PC with 39.1% DHA incorporation at 30min. The different DHA donors, including forms of fatty acid, methyl ester, and triglycerides, were compared. Molecular dynamics (MD) was used to illustrate the catalytic mechanism at the molecular level containing the diffusions of substrates, the structure-activity relationship of PLA1, and the effect of water content.

Study on the Transesterification of Phosphatidylcholine over Diethylamine

The catalyst diethylamine with low boiling point can be separated combined with the recovery of ethanol by distillation in the transesterification of phosphatidylcholine, and it was an effective catayst for preparing GPC from natural lecithin via transesterification. Under the conditions of: the catalyst content was 3.6% of the total reaction volume, lecithin concentration was 100 mmol/L , reaction temperature was 60 °C and reaction time was 260 min, the phosphatidylcholine was reacted completely and the yield of GPC can reach about 80%

Enzymatic modification of phosphatidylcholine with n-3 PUFA from silkworm oil fatty acids

α-Linolenic acid (ALA) containing phosphatidylcholine (PC) was prepared by an enzymatic method employing natural substrates comprising of egg and eri silkworm oil. Eri silkworm oil extracted from eri pupae was saponified to obtain the fatty acid mixture which was further subjected to urea complexation to obtain an ALA rich fraction with a purity of about 93%. Transesterification of PC with the ALA rich fraction with three immobilized lipases namely Lipozyme TL IM, Lipozyme RM IM and lipase from Candida Antarcticaz showed that only the lipase from Candida antarctica was successful for the incorporation of ALA into egg yolk PC. It was found that ALA was incorporated by up to 27% in the sn -1 position of egg PC and the positional distribution analysis of fatty acids in the modified PC showed that the sn -1 position was found to contain about 59% ALA.

Preparing L‐α‐Glycerophosphocholine in a Phase‐Transfer Catalytic Reaction: Kinetic Study

ABSTRACTThe transesterification of phosphatidylcholine with methanol was successfully carried out using a promising solvent methyl tert‐butyl ether instead of traditional ether, and the reaction was dramatically enhanced in the presence of tetrabutylammonium hydroxide as the phase‐transfer catalyst. Kinetics of the reaction including the effects of the reaction conditions on the conversion of phosphatidylcholine and the apparent rate constant (kapp) were investigated in detail. On the basis of the experimental evidence, the transesterification mechanism was proposed and a kinetic model was developed, and the experimental data were well described by the pseudo–first‐order equation.

Study on the preparation of l-α-glycerophosphocholine catalyzed by low boiling point organic amines

The transesterification of phosphatidylcholine (PC for short) catalyzed by 12 kinds of low boiling point amines was examined under mild conditions to prepare l-α-glycerophosphocholine (GPC for short). The amines were confirmed as effective catalysts for GPC production, and the process using this kind of catalyst would be much simpler, since the recovery of the catalysts can be combined with the recovery of methanol by distillation. Three kinds of amines with boiling points lower than 50 °C and higher activities were applied to produce GPC, the yield of GPC could reach 90 % with a catalyst content of 2.4 %. The mechanism of the methanolysis catalyzed by the primary amine was proposed and the experimental data fit the equation model well. Isopropylamine showed better activity with higher yield of GPC and lower activation energy than others. Gas Chromatography and 1H NMR were used to analyze the product, which indicated that the product had high purity and there was no reaction between the catalyst and other materials. The catalyst could get similar effect to the fresh after repeated uses.

Transesterification of phosphatidylcholine in sn-1 position through direct use of lipase-producing Rhizopus oryzae cells as whole-cell biocatalyst

The enzymatic process presents an advantage of producing specified phospholipids that rarely exist in nature. In this study, we investigated the regiospecific modification of phosphatidylcholine (PC) in the sn-1 position using immobilized Rhizopus oryzae. In a reaction mixture containing egg yolk PC and exogenous lauric acid (LA) in n-hexane, lipase-producing R. oryzae cells immobilized within biomass support particles (BSPs) showed a much higher transesterification activity than lipase powders. To improve the product yield, several parameters including substrate ratio and reaction time were investigated, resulting in the incorporation of 44.2% LA into the product PC after a 48-h reaction. The analysis of the molecular structure showed that a large proportion of exogenous LA (>90%) was incorporated in the sn-1 position of the enzymatically modified PC. Moreover, the BSP-immobilized R. oryzae maintained its activity for more than 12 batch cycles. The presented results, therefore, suggest the applicability of BSP-immobilized R. oryzae as a whole-cell biocatalyst for the regiospecific modification of phospholipids.

Transformation of Phospholipids by Cabbage Phospholipase D in Mixed Micelles Containing 3-[(3-Cholamidopropyl)dimethylammonio]-1-propanesulfonate

We compared the activities of cabbage phospholipase D during hydrolysis and transesterification of phosphatidylcholine in mixed micelles of surface-active compounds with various physicochemical properties. Mixed micelles of phospholipids and 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (ratio, 1:2) were among the best substrates. Hydrolysis and transphosphatidylation were studied in micelles containing 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate. Mixed micelles of phosphatidylcholine and 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate may serve as a new substrate for measurements of phospholipase D activity and preparative isolation of phospholipids using this enzyme.

Transesterification of phosphatidylcholine with eicosapentaenoic acid ethyl ester using phospholipase A2 in organic solvent

Phospholipase A2-catalysed transesterification of phosphatidylcholine (PC, 99%) with eicosapentaenoic acid ethyl ester (EPAEE, 95%) was carried out in organic solvent. The maximum yield was 14.3% (w/w). The optimum reaction condition was 50 °C, 48 h, initial water activity 0.25 and molar ratio of PC to EPAEE 1:10 in 5 ml toluene.

Lipase‐catalyzed transesterification of phosphatidylcholine at controlled water activity

The incorporation of a free fatty acid into thesn‐1 position of phosphatidylcholine by lipase‐catalyzed transesterification was investigated. The thermodynamic water activity of both the enzyme preparation and the substrate solution was adjusted to the same value prior to the reaction. The reaction rate increased with increasing water activity but the yield of modified phosphatidylcholine decreased due to hydrolysis. By using a large excess of the free fatty acid (heptadecanoic acid), the hydrolysis reaction was slowed down, so a higher yield was obtained at a given degree of incorporation. The best results were obtained withRhizopus arrhizus lipase immobilized by adsorption on a polypropylene support. With this preparation, a yield of 60% and nearly 50% incorporation of heptadecanoic acid (100% incorporation in thesn‐1 position) was obtained at a water activity of 0.064. The enzyme preparation had good operational stability and position specificity. Little incorporation (<1%) was observed in thesn‐2 position, when almost all the fatty acid in thesn‐1 position was exchanged.

Synthesis of phosphatidylcholine with (n−3) fatty acids by phospholipase A 2 in microemulsion

Phosphatidylcholine containing a long chain polyunsaturated acyl group at the 2‐position has been prepared by phospholipase A 2 catalyzed esterification of lysophosphatidylcholine with polyunsaturated fatty acids EPA (C20∶5) or DHA (C22∶6). Preliminary studies showed that the other fatty acids, such as lauric acid (C12), palmitic acid (C16), stearic acid (C18) and linoleic acid (C18∶2), were also incorporated. To our knowledge, phospholipase A 2 catalyzed condensation reactions have not been reported in the literature before. The reactions were performed in sodiumbis(2‐ethylhexyl)‐sulfosuccinate‐based microemulsions containing small amounts of water. Synthesis of the same phospholipid by transesterification of phosphatidylcholine with the polyunsaturated acids in microemulsion failed; however, enzymatic hydrolysis to lysophosphatidylcholine was facile, quantitative conversion from phosphatidylcholine being attained after 16 hr reaction time.An additional observation was that, unlike enzymatic hydrolysis of phospholipids, the condensation reaction catalyzed by phospholipase A 2 was totally independent of the presence of calcium.