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Query: UMLS:C0027960 (mole)
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Five lipases, namely, Candida antarctica (Novozyme-435), Mucor miehei (Lipozyme-IM), Pseudomonas sp. (PS-30), Aspergillus niger (AP-12), and Candida rugosa (AY-30), were screened for their effect on catalyzing the acidolysis of tristearin with selected long-chain fatty acids. Among the lipases tested C. antarctica lipase catalyzed the highest incorporation of oleic acid (OA, 58.2%), gamma-linolenic acid (GLA, 55.9%), eicosapentaenoic acid (EPA, 81.6%), and docosahexaenoic acid (DHA, 47.7%) into tristearin. In comparison with other lipases examined, C. rugosa lipase catalyzed the highest incorporation of linoleic acid (LA, 75.8%), alpha-linolenic acid (ALA, 74.8%), and conjugated linoleic acid (CLA, 53.5%) into tristearin. Thus, these two lipases might be considered promising biocatalysts for acidolysis of tristearin with selected long-chain fatty acids. EPA was better incorporated into tristearin than DHA using the fifth enzymes. LA incorporation was better than CLA. ALA was more reactive than GLA during acidolysis, except for the reaction catalyzed by Pseudomonas sp., possibly due to structural differences (location and geometry of double bonds) between the two fatty acids. In another set of experiments, a combination of equimolar quantities of unsaturated C18 fatty acids (OA + LA + CLA + GLA + ALA) was used for acidolysis of tristearin to C18 fatty acids at ratios of 1:1, 1:2, and 1:3. All lipases tested catalyzed incorporation of OA and LA into tristearin except for M. miehei, which incorportaed only OA. C. rugosa lipase better catalyzed incorporation of OA and LA into tristearin than other lipases tested, whereas the lowest incorporation was obtained using Pseudomonas sp. As the mole ratio of substrates increased from 1 to 3, incorporation of OA and LA increased except for the reaction catalyzed by A. niger and C. rugosa. All lipases tested failed to allow GLA or CLA to participate in the acidolysis reaction, and ALA was only slightly incoporated into tristearin when M. miehei was used.
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PMID:Acidolysis of tristearin with selected long-chain fatty acids. 1728 39

The effect of organic solvents on the equilibrium position of lipase-catalyzed esterification of glycerol and decanoic acid has been investigated. The reaction is carried out in an aqueous-organic two-phase system. In polar solvents, high mole fractions of monoacylglycerol and low mole fractions of triacylglycerol and measured, while in nonpolar solvents, the measured differences in the mole fractions of monodi-, and triacylglycerols are less. There is a good correlation between the ester mole fractions at equilibrium and the log P of the solvent (partition coefficient in n-octanolwater), however, only if the group of tertiary alcohols is excluded. In the plot of the easter mole fractions as a function of the logarithm of hte solubility of water in the organic solvent, the tertiary alcohols can be included; however, in this case other deviations appear.For the prediction of the effect of organic solvents on the ester mole fractions at reaction equilibrium in nondilute reaction systems with a water activity below 1, the program TREP (Two-phase Reaction Equilibrium Prediction) is developed, which is based on the UNIFAC group contribution method. With this model the equilibrium data are essentially predicted from basic thermodynamic data. The required equilibrium constants are estimated from experiments without an organic solvent in the reaction medium. The mole fractions calculated by TREP show the same trends as the experimentally measured mole fractions; however, some variation is observed in the absolute values. These deviations may be due to inaccuracies in the UNIFAC group contribution method. TREP is found to be a correct method to predict within some limits the ester mole fractions at equilibrium for all mixtures of solvents, substrates, and products. The production of monoester can be enhanced in reaction system with a sufficient high concentration of a polar solvent. In experiments with a triglymeto-decanoic acid ratio of 5, almost no di-and triesters can be detected at equilibrium.
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PMID:The effect of organic solvents on the equilibrium position of enzymatic acylglycerol synthesis. 1860 Dec 50

Refined olive pomace oil (ROPO) was utilized as a source oil for production of cocoa butter-like fat. Immobilized sn-1,3 specific lipase catalyzed acidolysis of ROPO with palmitic (PA) and stearic (SA) acids was performed in a laboratory scale packed-bed reactor. Effect of reactor conditions on product formation was studied at various substrate mole ratios (ROPO:PA:SA; 1:1:1, 1:1:3, 1:3:3, 1:2:6), enzyme loads (10%, 20%, 40%), substrate flow rates (1.5, 4.5, 7.5, 15 ml/min) and solvent amounts (150, 400 ml). The highest yield (10.9% POP, 19.7% POS and 11.2% SOS) was obtained at 40% enzyme load, 1:2:6 substrate mole ratio, 45 degrees C, 7.5 ml/min substrate flow rate, 150 ml solvent and 3h reaction time. The melting profile and SFC of the product were comparable to those of CB. Polarized light microscope (PLM) images showed no drastic changes in polymorphic behavior between CB and product.
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PMID:Conversion of olive pomace oil to cocoa butter-like fat in a packed-bed enzyme reactor. 1860 38

The lipase-catalyzed acylglycerol synthesis with fatty acids of different chain length is studied. Measured ester mole fractions at equilibrium are compared with calculated mole fractions. For these calculations the computer program TREP (Two-phase Reaction Equilibrium Prediction) is used. This program is based on the UNIFAC group contribution method and is developed for nondilute two-phase reaction systems.With one set of equilibrium constants, namely 1.3, 0.8, and 0.6 for monoester, diester, and triester synthesis, respectively, the equilibrium position of the reaction between glycerol and all saturated fatty acids with a chain length from 6 to 18 and oleic acid (cis-9-octadecenoic acid) can be calculated. Deviations, expressed as the ratio between calculated and measured ester mole fractions, usually were between 0.7 and 1.2. In the presence of solvents, the deviations of the monoester mole fractions were higher and rose up to 3. Without addition of a solvent, the ester mole fractions at equilibrium are dependent on the fatty acid chain length. With the short-chain hexanoic acid, the monoester mole fraction is the highest ester mole fraction, while for the long-chain oleic acid, the diester mole fraction is the highest one. The ester mole fractions become independent on the chain length of the fatty acid with a solvent added in a sufficient high concentration. Both reactions, with saturated and unsaturated C(18) fatty acids, lead to the same equilibrium position. The program TREP is found to make good predictions of the equilibrium amounts of ester and fatty acid. However, systematic deviations arise between measured and calculated amounts of water and glycerol in the organic phase. The calculated water and glycerol amounts are always lower than the measured ones. These deviations seem to be highest in nonpolar media and are probably due to deficiencies in the UNIFAC calculation method. Some preliminary experiments show the effect of the choice of solvent on the reaction rates. In polar solvents, the monoester production rate is enhances by a factor of 1.5 as compared to the reaction rate in a system without solvent.
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PMID:Solvent effects on lipase-catalyzed esterification of glycerol and fatty acids. 1861 44

Lipolase and Lipozyme are produced in large quantities (as a result of genetic engineering and overexpression) for the detergents market and provide a cheap source of highly active biocatalysts. Humicola lanuginosa lipase (HIL) and Rhizomucor miehei lipase (RmL) have been isolated in partially purified form from commercial preparations of Lipolase and Lipozyme, respectively. These lipases were solubilized in Aerosol-OT (AOT)-stabilized water-in-oil (w/o) microemulsions in n-heptane. HIL and RmL activity in these microemulsions was assayed by spectrophotometric measurement of the initial rate of p-nitophenyl butyrate hydrolysis, and by chromatographic determination of the initial rate of octyl decanoate synthesis from 1-octanol and decanoic acid. The hydrolytic activity of HIL in microemulsions measured as a function of buffer pH prior to dispersal, followed a sigmoidal profile with the highest activities observed at alkaline pHs. This broadly matches the pH-activity profile for tributyrin hydrolysis by Lipolase in an aqueous emulsion assay. The hydrolytic activity of RmL in the same microemulsions, measured as a function of pH, gave a bell-shaped profile with a maximum activity at pH 7.5. Again, the observed pH-activity profile was similar to that reported for a purified RmL in a tributyrin-based aqueous emulsion assay. In contrast, the esterification activity exhibited by both HIL and RmL in AOT microemulsions over the available range pH 6.1 to 10.4, decreases as the pH increases, most likely reflecting the effect of substrate ionization. The dependence of the hydrolytic and condensation activity of HIL on R, the mole ratio of water to surfactant, were similar with both profiles exhibiting a maximum at R = 5. The hydrolytic and esterification activities of RmL followed similar R-dependent profiles, but the profiles in this case exhibited a maximum at R = 10. The water activities at these R values were directly measured as 0.78 and 0.9, respectively. Measured water activities were unperturbed by the presence of lipase at the concentrations used in these studies.
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PMID:Comparison of hydrolysis and esterification behavior of Humicola lanuginosa and Rhizomucor miehei lipases in AOT-stabilized water-in-oil microemulsions: I. Effect of pH and water content on reaction kinetics. 1862 62

Chromobacterium viscosum (CV) lipase was immobilized in gelatin-containing Aerosol-OT (AOT) microemulsion-based organogels (MBGs). The behavior of this novel, predominantly hydrophobic matrix as an esterification catalyst has been examined. The biocatalyst was most effective when the MBG was granulated to yield gel particles of approximately 500 mum diameter, providing a total surface area of ca. 10(6) mm(2) per 10 cm(3) of gel. The gel was generally contacted with a solution of the substrate(s) in a hydrocarbon oil. Under most conditions reaction was not diffusion limited. Apparent lipase activity was influenced by certain compositional changes in the MBG, but most significantly when the R value, the mole ratio of water to surfactant, was altered. Higher activities were observed at lower R values. Although gels of lowest R value expressed the highest condensation activity, such formulations were physically unsuitable as immobilization matrices due to their proximity to the gel-solution phase boundary. MBGs of intermediate R values (between 60 and 80) were considered most suitable because they offer relatively high condensation activity and good physical stability. The gelatin concentration also exerted a small but measurable influence on the observed condensation rates. Apparent lipase activity was also influenced to some extent by the nature of the parent hydrocarbon used to prepare the MBG. Higher activities were obtained using formulations derived from isooctane and cyclohexane rather than the n-alkanes. Condensation activities expressed by CV lipase in the MBGs were broadly comparable to those expressed in the analogous parent water-in-oil (w/o) microemulsions. The MBGs functioned effectively in neat substrate solutions, but the condensation activity expressed by the MBGs in a series of successive batch syntheses was adversely affected by the formation and retention of the water coproduct. Selective removal of the water was achieved using a concentrated solution of dry reverse micelles, which resulted in recovery of lost activity. Pretreatment of lipase-containing MBGs resulted in the formation of MBGs with enhanced catalytic properties and modified composing the conventional procedure. (c) 1997 John Wiley & Sons, Inc.
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PMID:Biocatalysis using gelatin microemulsion-based organogels containing immobilized Chromobacterium viscosum lipase. 1863 56

In the lipase (Novozyme 435)-catalyzed synthesis of ginsenoside Rb1 esters, different acyl donors were found to affect not only the degree of conversion but also the regioselectivity. The reaction of acyl donors with short carbon chain was more effective, showing higher conversion than those with long carbon chain. Among the three solvent systems, the reaction in tert-amyl alcohol showed the highest conversion rate, while the reaction in the mixed solvent of t-BuOH and pyridine (1:1) had the lowest conversion rate. To allow the increase of GRb1 lipophilicity, we decided to further study the optimal condition of synthesis of GRb1 with vinyl decanoate with 10 carbon chain fatty acids in tert-amyl alcohol. Response surface methodology (RSM) was employed to optimize the synthesis condition. From the ridge analysis with maximum responses, the maximum GRb1 conversion was predicted to be 61.51% in a combination of factors (40.2 h, 52.95 degrees C, substrate mole ratio 275.57, and enzyme amount 39.81 mg/mL). Further, the adequacy of the predicted model was examined by additional independent experiments at the predicted maximum synthesis conditions. Results showed that the RSM was effective to optimize a combination of factors for lipase-catalyzed synthesis of ginsenoside Rb1 with vinyl decanoate.
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PMID:Optimization of lipase-catalyzed synthesis of ginsenoside Rb1 esters using response surface methodology. 1898 61

1,3-Dioleoyl-2-palmitoylglycerol (OPO)-rich human milk fat substitute (HMFS) was synthesized from tripalmitin-rich fraction and ethyl oleate by a lipase-catalyzed interesterification. Response surface methodology was employed to optimize its OPO content and acyl migration with reaction factors - substrate mole ratio of PPP-rich fraction to ethyl oleate (1:4, 1:5 and 1:6), reaction temperature (50, 55 and 60 degrees C) and time (3, 7.5 and 12 hours). The predictive models for OPO content and acyl migration were adequate and reproducible. The OPO content increased with substrate ratio, and decreased with reaction time and temperature, whereas acyl migration increased with temperature and time. The optimal conditions for HMFS synthesis while maximizing OPO content (31.43% OPO) and minimizing acyl migration (6.07%) were predicted at the reaction combination of 50 degrees C, three hours and 5.5 substrate ratio. HMFS was resynthesized under the same condition, and no significant difference between the observed and predicted values was found. Further, the major fatty acid of HMFS was palmitic acid (80.6%) at sn-2 position, and oleic acid (64.9%) at sn-1,3 position.
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PMID:Optimized synthesis of 1,3-dioleoyl-2-palmitoylglycerol-rich triacylglycerol via interesterification catalyzed by a lipase from Thermomyces lanuginosus. 1987 84

Molecularly imprinted polymers (MIPs) have long been studied for applications in biomolecule recognition and binding; compared with natural antibodies, they may offer advantages in cost and stability. We report on the development of MIPs that "self-report" concentrations of bound analytes via fluorescence changes in embedded quantum dots (QDots). Composite QDot/MIPs were prepared using phase inversion of poly(ethylene-co-vinyl alcohol) (EVAL) solutions with various ethylene mole ratios in the presence of salivary target molecules (e.g. amylase, lipase, and lysozyme). These major protein components of saliva have been implicated as possible biomarkers for pancreatic cancer. The optimum (highest imprinting effectiveness) ethylene mole ratios of the commercially available EVALs were found to be 32, 38, and 44 mol% for the imprinting of amylase, lipase, and lysozyme, respectively. QD fluorescence quenching was observed on binding of analytes to composite MIPs in a concentration-dependent manner, and was used to construct calibration curves. Finally, the composite MIP particles were used for the quantitative detection of amylase, lipase, and lysozyme in real samples (saliva) and compared with a commercial Architect ci 8200 chemical analysis system.
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PMID:Optical recognition of salivary proteins by use of molecularly imprinted poly(ethylene-co-vinyl alcohol)/quantum dot composite nanoparticles. 2034 27

A novel plasmid (pBSR2) was constructed by incorporating a strong lipase promoter and a terminator into the original pBD64. The lipase gene from Bacillus subtilis strain IFFI10210 was cloned into the plasmid pBSR2 and transformed into B. subtilis A.S.1.1655 to obtain an overexpression strain. The recombinant lipase [BSL2 (B. subtilis lipase 2)] has been expressed from the novel constructed strain and used in kinetic resolution of glycidol through enantioselective transesterification. The effects of reaction conditions on the activity as well as enantioselectivity were investigated. BSL2 showed a satisfying enantioselectivity (E>30) under the optimum conditions [acyl donor: vinyl butyrate; the mole ratio of vinyl butyrate to glycidol was 3:1; organic medium: 1,2-dichloroethane with water activity (a(w))=0.33; temperature 40 degrees C]. The remaining (R)-glycidol with a high enantiomeric purity [ee (enantiomeric excess) >99%] could be obtained when the conversion was approx. 60%. The results clearly show a good potential for industrial application of BSL2 in the resolution of glycidol through enantioselective transesterification.
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PMID:Enantioselective transesterification of glycidol catalysed by a novel lipase expressed from Bacillus subtilis. 2039 73


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