- Stereospecific synthesis of phosphatidylglycerol using a cyanoethyl phosphoramidite precursor
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Phosphatidylglycerols (PG) are a family of naturally occurring phospholipids that are responsible for critical operations within cells. PG are characterized by an (R) configuration in the diacyl glycerol backbone and an (S) configuration in the phosphoglycerol head group. Herein, we report a synthetic route to provide control over the PG stereocenters as well as control of the acyl chain identity.
- Storch, Judith,Struzik, Zachary J.,Thompson, David H.,Weerts, Ashley N.
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- Glycerolysis of methyl oleate on MgO: Experimental and theoretical study of the reaction selectivity
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The liquid-phase MgO-promoted glycerolysis of methyl oleate, a fatty acid methyl ester (FAME), to give acylglycerol products was studied both, experimentally and by density functional theory (DFT). Catalytic results showed that strongly basic low coordination O2- surface sites participate in kinetically relevant steps of the glycerolysis reaction. Changes in the selectivity toward the different mono- and diglyceride isomers were investigated by varying the reaction conditions. The main product was always α-glyceryl monooleate (α-MG), a monoglyceride with the ester fragment at one of the terminal positions of the glycerol molecule; the β-MG isomer, with the ester substituted at position 2 was obtained in much lower amounts. The molecular modeling of glycerol (Gly) and FAME adsorptions as well as of the glycerolysis reaction was carried out using periodic DFT calculations and a model of stepped MgO surface. Results indicated that FAME was more weakly adsorbed than Gly; the latter adsorbs on a coordinatively unsaturated surface O2- site with O-H bond breaking at position 2 of the Gly molecule, giving therefore a surface β-glyceroxide species. Calculations explained the apparent contradiction between the preferential formation of the α-MG isomer and the energetically favored dissociation of the secondary OH group of Gly that leads to the β-glyceroxide species. They predict that the β-glyceroxide species participates in the pathways conducting to both, α- and β-MG isomers. Synthesis of α-MG occurs by C-O coupling of β-glyceroxide with FAME at one of the two primary OH groups of the β-glyceroxide species. Two transition states (TS) and a tetrahedral intermediate (TI) are involved in both, α-MG and β-MG isomer formation. However, the pathway toward β-MG is limited by the large sterical effects associated to the TI formation. Contrarily, the TI leading to α-MG is relatively easy to form.
- Belelli,Ferretti,Apesteguía,Ferullo,Di Cosimo
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p. 132 - 144
(2015/09/28)
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- An insight into the solvent effect on the positional selectivity of the immobilized lipase from Burkholderia cepacia in 1,3-diolein synthesis
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The solvent effect on the positional selectivity of the immobilized lipase from Burkholderia cepacia in 1,3-diolein synthesis was investigated for the first time. The results indicated that the preferential selectivity to sn-1 hydroxyl of the glycerol molecule over sn-2 hydroxyl was weaker in solvents with higher logP values.
- Bi, Yan-Hong,Wang, Zhao-Yu,Duan, Zhang-Qun,Zhao, Xiang-Jie,Chen, Xiao-Ming,Nie, Ling-Hong
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p. 23122 - 23124
(2015/06/02)
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- Highly efficient solvent-free synthesis of 1,3-diacylglycerols by lipase immobilised on nano-sized magnetite particles
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Recently, 1,3-DAGs (1,3-diacylglycerols) have attracted considerable attention as healthy components of food, oil and pharmaceutical intermediates. Generally, 1,3-DAG is prepared by lipase-mediated catalysis in a solvent free system. However, the system's high reaction temperature (required to reach the reactants' melting point), high substrate concentration and high viscosity severely reduce the lipase's activity, selectivity and recycling efficiency. In this report, MjL (Mucor javanicus lipase) was found to have the best performance in the solvent-free synthesis of 1,3-DAGs of several common commercial lipases. By covalent binding to amino-group-activated NSM (nano-sized magnetite) particles and cross-linking to form an enzyme aggregate coat, MjL's specific activity increased 10-fold, and was able to be reused for 10 cycles with 90% residual activity at 55 °C. 1,3-DAGs of lauric, myristic, palmitic, stearic, oleic and linoleic acid were prepared using the resulting immobilised enzyme, all with yields greater than 90%, and the reaction time was also greatly reduced.
- Meng, Xiao,Xu, Gang,Zhou, Qin-Li,Wu, Jian-Ping,Yang, Li-Rong
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p. 319 - 324
(2013/10/08)
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- 1-O-Alkyl (di)glycerol ethers synthesis from methyl esters and triglycerides by two pathways: Catalytic reductive alkylation and transesterification/reduction
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From available and bio-sourced methyl esters, monoglycerides or oleic sunflower refined oil, the corresponding 1-O-alkyl (di)glycerol ethers were obtained in both high yields and selectivity by two different pathways. With methyl esters, a reductive alkylation with (di)glycerol was realized under 50 bar hydrogen pressure in the presence of 1 mol% of Pd/C and an acid co-catalyst. A second two step procedure was evaluated from methyl esters or triolein and consisted of a first transesterification to the corresponding monoglyceride with a BaO/Al2O3 catalyst, then its reduction to the desired glycerol monoether with a recyclable heterogeneous catalytic system Pd/C and Amberlyst 35 under H2 pressure. In addition, a mechanism for the reaction was also proposed.
- Sutter, Marc,Dayoub, Wissam,Metay, Estelle,Raoul, Yann,Lemaire, Marc
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supporting information
p. 786 - 797
(2013/04/24)
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- Zirconium phenyl phosphonate phosphite as a highly active, reusable, solid acid catalyst for producing fatty acid polyol esters
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The application of zirconium phenyl phosphonate phosphite (ZrPP) as a solid acid catalyst for producing polyol esters by esterification of glycerol or trimethylolpropane with a fatty acid (C8-C18.1) is reported for the first time. ZrPP exhibits high catalytic activity and in particular, (di + tri) esters selectivity (92.3 mol%). These esters of polyols are known for their application as biolubricants. The catalyst prepared using phosphorous acid to phenyl phosphonic acid molar ratio of 3:1 was found superior. The influence of process parameters on activity and selectivity of the catalyst was investigated. ZrPP was reusable in at least three recycling experiments. Hydrophobicity due to exposed phenyl groups on the surface is the possible cause for superior esterification activity of this novel, solid catalyst.
- Varhadi, Poonam,Kotwal, Mehejabeen,Srinivas
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p. 129 - 136
(2013/07/26)
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- Evaluation of Rhizopus oryzae lipase for the determination of regiodistribution in triacylglycerols with medium chain fatty acids
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The nutritional profile and rheological behaviors of lipids is both due to fatty acid composition and regiodistribution on external and internal positions of triacylglycerol. Actual methods for regiodistribution analysis having some restrictions, there is still a need for investigating a safe, simple and environmentally friendly method for the sn-2 position analysis that could especially be used for the analysis of fats containing medium and short chain fatty acids. The objective of this study was to evaluate the 1,3-selectivity and typoselectivity of Rhizopus oryzae lipase in the presence of short/medium chain fatty acids in partial hydrolysis conditions used for regiodistribution analysis. Structured triacylglycerols containing eight-carbon-chain length fatty acids in the sn -2 position were chemically synthesized using DCC/DMAP coupling agent and purification steps by flash-chromatography. The final product showed very high purity and was used as the substrate for 1,3-selectivity evaluation. Typoselectivity was assessed by investigating partial hydrolysis of equimolar blends of homogeneous TAG. This study confirmed the 1,3-selectivity of Rhizopus oryzae lipase in the hydrolysis conditions used, and revealed that this lipase was less influenced by fatty acids chain length than pancreatic lipase. Considering this, Rhizopus oryzae lipase appeared to be a good candidate for regiodistribution analysis of fats containing medium and short chain fatty acids.
- Perignon, Marlene,Lecomte, Jerome,Pina, Michel,Renault, Anne,Simonneau-Deve, Camille,Villeneuve, Pierre
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experimental part
p. 89 - 96
(2012/04/04)
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- Glycerol acyl-transfer kinetics of a circular permutated Candida antarctica lipase B
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Triacylglycerols containing a high abundance of unusual fatty acids, such as γ-linolenic acid, or novel arylaliphatic acids, such as ferulic acid, are useful in pharmaceutical and cosmeceutical applications. Candida antarctica lipase B (CALB) is quite often used for non-aqueous synthesis, although the wild-type enzyme can be rather slow with bulky and sterically hindered acyl donor substrates. The catalytic performance of a circularly permutated variant of CALB, cp283, with various acyl donors and glycerol was examined. In comparison to wild-type CALB, butyl oleate and ethyl γ-linolenate glycerolysis rates were 2.2- and 4.0-fold greater, respectively. Cp283 showed substrate inhibition by glycerol, which was not the case with the wild-type version. With either ethyl ferulate or vinyl ferulate acyl donors, cp283 matched the performance of wild-type CALB. Changes in active site accessibility resulting from circular permutation led to increased catalytic rates for bulky fatty acid esters but did not overcome the steric hindrance or energetic limitations experienced by arylaliphatic esters.
- Laszlo, Joseph A.,Yu, Ying,Lutz, Stefan,Compton, David L.
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scheme or table
p. 175 - 180
(2012/07/01)
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- Optimization of Candida sp. 99-125 lipase catalyzed esterification for synthesis of monoglyceride and diglyceride in solvent-free system
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Esterification of glycerol and oleic acid catalyzed by lipase Candida sp. 99-125 was carried out to synthesize monoglyceride (MAG) and diglyceride (DAG) in solvent-free system. Beta-cyclodextrin as an assistant was mixed with the lipase powder. Six reaction variables, initial water content (0-14 wt% of the substrate mass), the glycerol/oleic acid molar ratio (1:1-6:1), catalyst load (3-15 wt% of the substrate mass), reaction temperature (30-60 °C), agitator speed (130-250 r/min) and beta-cyclodextrin/lipase mass ratio (0-2) were optimized. The optimal conditions to the synthesis of MAG and DAG were different: the optimal glycerol/oleic acid molar ratio, beta-cyclodextrin/lipase mass ratio, catalyst load and reaction temperature were 6:1, 0, 5%, 50 °C for MAG, and 5:1, 1.5, 10%, 40 °C for DAG, respectively. The optimal water content and agitator speed for both MAG and DAG were 10% and 190 r/min, respectively. Under the optimal conditions, 49.6% MAG and 54.3% DAG were obtained after 8 h and 4 h, respectively, and the maximum of 81.4% MAG plus DAG (28.1% MAG and 53.3% DAG) was obtained after 2 h under the DAG optimal condition. Above 90% purity of MAG and DAG can be obtained by silica column separation.
- Zhao, Yanjun,Liu, Junfeng,Deng, Li,Wang, Fang,Tan, Tianwei
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body text
p. 157 - 162
(2012/07/01)
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- MgO-based catalysts for monoglyceride synthesis from methyl oleate and glycerol: Effect of Li promotion
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The synthesis of monoglycerides (glyceryl monooleates) by heterogeneously catalyzed glycerolysis of an unsaturated fatty acid methyl ester (methyl oleate) was studied on MgO and Li-promoted MgO catalysts. Several MgO-based catalysts with different Li loadings were prepared by incipient wetness impregnation and characterized by XRD, N2 physisorption, and FTIR and TPD of CO 2 among other techniques. Promotion of MgO with lithium, a basic promoter, affected the textural and structural properties of the resulting oxides so that more crystalline MgO phases with decreased surface area were obtained at increasing Li contents. Furthermore, the addition of Li generated new strong base sites because of formation of dispersed surface Li2O species, and thereby increased the total base site density of parent MgO. Li-containing MgO catalysts efficiently promoted the glycerolysis reaction, achieving high monoglyceride yields (70-73%) at 493 K. The initial monoglyceride formation rate increased linearly with the Li content on the sample following the enhanced overall catalyst base strength. Although conversions at the end of the run were ≈100% for all the catalysts, the monoglyceride selectivity slightly decreased with the Li loading, probably as a consequence of the less surface affinity for glycerol adsorption that facilitates competing monoglyceride re-adsorption and transformation to diglycerides by consecutive glycerolysis or disproportionation reactions.
- Ferretti,Apesteguía,Di Cosimo
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experimental part
p. 146 - 153
(2012/02/01)
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- Synthesis and properties of ascorbyl esters catalyzed by lipozyme TL im using triglycerides as acyl donors
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Esters of l-ascorbic acid with long-chain fatty acids (E-304) are employed as antioxidants in foods rich in lipids. Although their enzymatic synthesis offers some advantages compared with the current chemical processes, most of the reported methods employ the immobilized lipase from Candida antarctica as biocatalyst and free fatty acids or activated esters as acyl donors. In order to diminish the cost of the process, we have investigated the synthesis of ascorbyl oleate and ascorbyl palmitate esters with the immobilized Thermomyces lanuginosus lipase Lipozyme TL IM-which is significantly less expensive than Novozym 435-and triglycerides as source of fatty acids. Lipozyme TL IM gave rise to a lower yield of 6-O-ascorbyl oleate than Novozym 435 when using triolein (64 vs. 84%) and olive oil (27 vs. 33%) as acyl donors. Both 6-O-ascorbyl oleate and 6-O-ascorbyl palmitate displayed excellent surfactant and antioxidant properties. The Trolox Equivalent Antioxidant Capability values for the oleate and palmitate were 71 and 84%, respectively, of those obtained with l-ascorbic acid; however, both derivatives were able to stabilize soybean oil towards peroxide formation.
- Reyes-Duarte,Lopez-Cortes,Torres,Comelles,Parra,Pena,Ugidos,Ballesteros,Plou
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scheme or table
p. 57 - 64
(2011/10/04)
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- Study on acyl migration kinetics of partial glycerides: Dependence on temperature and water activity
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Acyl migration phenomenon was often observed during 1,3-positional specificity lipase-catalyzed reactions from triglycerides and partial glycerides, including acyl migration of 1,2-diglyceride (1,2-DG) to 1,3-diglyceride (1,3-DG) and 2-monoglyceride (2-MG) to 1-monoglyceride (1-MG). However, the acyl migration mechanism and kinetics were seldom studied despite of numerous researches on process optimization of 1,3-positional specificity lipase-catalyzed reaction. In this paper, the influence of related factors on acyl migration process as well as their influencing mechanism was further studied. It was found that temperature and water activity were two crucial factors that would influence acyl migration kinetics. Determination of the kinetic parameters under different temperatures revealed that the acyl migration reaction rates were greatly promoted by the increasing of temperature. The acyl migration rates of 1,2-diglyceride and 2-monoglyceride were quite different from each other, which was found to be due to the different activation energies. Further study of how would water influence the acyl migration process showed that water activity rather than water content was a key factor that influenced acyl migration and the acyl migration rate would decrease with the increase of water activity. It was further revealed that water activity influenced the charge dispersion of the transition state, which ultimately influenced the reaction activation energy and then influenced the acyl migration rate.
- Li, Wei,Du, Wei,Li, Qiang,Sun, Ting,Liu, Dehua
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scheme or table
p. 17 - 22
(2010/10/19)
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- The pronounced effect of water activity on the positional selectivity of Novozym 435 during 1,3-diolein synthesis by esterification
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We have investigated the effect of water activity on the positional selectivity of the immobilized lipase Novozym 435 during the esterification of oleic acid with glycerol for 1,3-diolein preparation. The highest preferential selectivity of Novozym 435 to
- Duan, Zhang-Qun,Du, Wei,Liu, De-Hua
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experimental part
p. 356 - 358
(2010/11/16)
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- Biochemical characterization of the cutinases from Thermobifida fusca
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Thermobifida fusca produces two cutinases which share 93% identity in amino acid sequence. In the present study, we investigated the detailed biochemical properties of T. fusca cutinases for the first time. For a better comparison between bacterial and fungal cutinases, recombinant Fusarium solani pisi cutinase was subjected to the similar analysis. The results showed that both bacterial and fungal cutinases are monomeric proteins in solution. The bacterial cutinases exhibited a broad substrate specificity against plant cutin, synthetic polyesters, insoluble triglycerides, and soluble esters. In addition, the two isoenzymes of T. fusca and the F. solani pisi cutinase are similar in substrate kinetics, the lack of interfacial activation, and metal ion requirements. However, the T. fusca cutinases showed higher stability in the presence of surfactants and organic solvents. Considering the versatile hydrolytic activity, good tolerance to surfactants, superior stability in organic solvents, and thermostability demonstrated by T. fusca cutinases, they may have promising applications in related industries.
- Chen, Sheng,Su, Lingqia,Billig, Susan,Zimmermann, Wolfgang,Chen, Jian,Wu, Jing
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experimental part
p. 121 - 127
(2010/10/19)
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- An isozyme of earthworm serine proteases acts on hydrolysis of triacylglycerol
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An enzyme catalyzing the hydrolysis of triacylglycerol was purified from an earthworm. The N-terminal amino acid sequence and the catalytic function of the purified enzyme were identical to those of Isozyme C, an isozyme of the earthworm-serine proteases. No other lipase proteins were found in the earthworm cells. The isozyme might act on the hydrolysis of triacylglycerol as well as the protein decomposition.
- Nakajima, Nobuyoshi,Sugimoto, Manabu,Tsuboi, Sadao,Tsuji, Hideaki,Ishihara, Kohji
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p. 2009 - 2011
(2008/02/03)
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- Enzymatic synthesis of symmetrical 1,3-diacylglycerols by direct esterification of glycerol in solvent-free system
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1,3-Diacylglycerols were synthesized by direct esterification of glycerol with free fatty acids in a solvent-free system. Free fatty acids with relatively low melting points (45°C) such as unsaturated and medium-chain saturated fatty acids were used. With stoichiometric ratios of the reactants and water removal by evaporation at 3 mm Hg vacuum applied at 1 h and thereafter, the maximal 1,3-diacylglycerol content in the reaction mixture was: 84.6% for 1,3-dicaprylin, 84.4% for 1,3-dicaprin, 74.3% for 1,3-dilinolein, 71.7% for 1,3-dieicosapentaenoin, 67.4% for 1,3-dilaurin, and 61.1% for 1,3-diolein. Some of the system's parameters (temperature, water removal, and molar ratio of the reactants) were optimized for the production of 1,3-dicaprylin, and the maximal yield reached 98%. The product was used for the chemical synthesis of 1,3-dicapryloyl-2-eicosapentaenoylglycerol. The yield after purification was 42%, and the purity of the triacylglycerol was 98% (both 1,3-dicapryloyl-2-eicosapentaenoylglycerol and 1,2-dicapryloyl-3-eicosapentaenoylglycerol included) by gas chromatographic analysis, of which 90% was the desired structured triacylglycerol (1,3-dicapryloyl-2-eicosapentaenoylglycerol) as determined by silver ion high-performance liquid chromatographic analysis.
- Rosu, Roxana,Yasui, Mamoru,Iwasaki, Yugo,Yamane, Tsuneo
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p. 839 - 843
(2007/10/03)
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- Enzymatic esterification of glycerol III. Lipase-catalyzed synthesis of regioisomerically pure 1,3-sn-diacylglycerols and 1(3)-rac-monoacylglycerols derived from unsaturated fatty acids
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Lipases that display high regioselectivities and broad substrate tolerance were used as catalysts for the efficient esterification of glycerol under the conditions of irreversible acyl transfer. A variety of unsaturated fatty acids, such as oleic, linoleic, erucic, ricinolic, hydroxystearic and coriolic acid, were used for this purpose in the form of their vinyl esters. Suitable biocatalysts were chosen on the basis of systematic screening experiments regarding their regioselectivities (RE) and substrate tolerances. Distinct differences were found and expressed in numerical RE values as a measure for differences of these biocatalysts as being specific, selective, and nonspecific. Based on these experiments, a variety of molecules were synthesized on a preparative scale (>150 mmol) in good yield (ca. 85%) and with high regioisomerical purities (>95% RE).
- Waldinger,Schneider
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p. 1513 - 1519
(2007/10/03)
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- A new catalyst for the preparation of oleate of glycerin
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In this investigation sulfate promoted titanium oxide (SPTO) is used to prepare oleate of glycerin, an excellent internal lubricant for manufacturing transparent sheet materials of polyvinylchloride (PVC).Experimental results show that the occasional saponification caused by the conventional sodalye catalyst for preparing oleate of glycerin can be avoided completely.SPTO can be used repeatedly without any special treatment.Its activity is comparable with that of sodalye.Also the use of SPTO can produce the desirable product composition.SPTO is likely to become a new catalyst for the production of oleate of glycerin.
- Rongsheng, Li,Hua, Yang,Wuyang, Zhang,Quan, Wei,Naixiang, Wei
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p. 449 - 451
(2007/10/02)
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- Substrate Specifity and Mode of Action of the Lipase Produced by Pseudomonas fragi 22.39 B
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The lipase purified from Pseudomonas fragi 22.39 B hydrolyzed not only triglycerides but also synthetic esters such as Tween, Span and methyl oleate.Of the saturated monoacid triglycerides tested, tributyrin was hydrolyzed most quickly.The lipase did not produce 1,3-diolein as a hydrolysis product from triolein.The addition of the Ca2+ ion to the reaction mixture promoted the hydrolysis rate for triglycerides and monoesters with longer-chain fatty acids (C14, C16, C18).The enzyme could hydrolyze various kinds of natural fats and oils, and the extent their hydrolysis reached above 90 percent.
- Nishio, Toshiyuki,Chikano, Takahide,Kamimura, Minoru
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p. 2525 - 2530
(2007/10/02)
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