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1.
Sobhi Basheer Ken-ichi Mogi Mitsutoshi Nakajima 《Journal of the American Oil Chemists' Society》1995,72(5):511-518
The kinetics of lipase-catalyzed interesterification of triglycerides and fatty acids in organic media was studied. First,
the lipase Saiken 100,Rhizopus japonicus, was modified by surfactant to form an enzyme precipitate in aqueous solution, which was well dispersed in organic solvents.
This modified lipase catalyzed the interesterification of tripalmitin and stearic acid. The enzyme has 1,3-positional specificity
and does not distinguish between stearic and palmitic acids. The kinetic model developed to describe the interesterification
reaction system is based on mass balance of two consecutive second-order reversible reactions. The reaction rate constant,
k, was determined by solving the differential rate equations of the reaction system and by expressing the value of k as a
function of concentrations of the substrates with time. The model gave satisfactory results. The best value of the specific
reaction rate constant k* that fits all experimental data was 1.2 · 10−5 [L2/(mmol · mg biocatalyst · h)] under the reaction conditions in this study. 相似文献
2.
B Camacho Paez A Robles Medina F Camacho Rubio L Esteban Cerdn E Molina Grima 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2003,78(4):461-470
The influence of the molar ratio caprylic acid/triolein, enzyme concentration and water content on the kinetics of the interesterification reaction of triolein (TO) and caprylic acid (CA) were studied. The enzyme used was the 1,3‐specific Rhizomucor miehei lipase. Data modelling was based on a simple scheme in which the acid was only incorporated in positions 1 and 3 of the glyceride backbone. In addition, it was assumed that positions 1 and 3 of the triglycerides were equivalent and that the events at position 1 did not depend on the nature of the fatty acid in position 3 and vice versa. Monoglycerides and diglycerides were not detected during the experiments. This was attributed to the low water content of the immobilised enzyme particles. The value of the equilibrium constant, K, for the exchange of caprylic and oleic acids was 2.7, which indicated that the incorporation of caprylic acid into triglycerides was favoured compared with the incorporation of oleic acid. Simple first order kinetics could describe the interesterification reaction. Using this model and the calculated equilibrium constant, the apparent kinetic constants were calculated. The model fitted all the experimental data except for the CA/TO molar ratios larger than 6. Moreover, the interesterification reaction rate had a maximum value at CA/TO molar ratios of 4–6 mol mol?1. Copyright © 2003 Society of Chemical Industry 相似文献
3.
Sobhi Basheer Uri Cogan Mitsutoshi Nakajima 《Journal of the American Oil Chemists' Society》1998,75(12):1785-1790
The esterification reaction kinetics of long-chain fatty acids and fatty alcohols catalyzed with a surfactant-coated lipase
in a microaqueous n-hexane system were studied. The biocatalytic complex, surfactant-lipase adduct, showed 40 times the activity after a reaction
time of 5 h compared to the unmodified lipase in the same reaction system. Various factors that may affect the activity of
the modified lipase were studied, such as the influence of substrate fatty acid chainlength, water content, and temperature.
By varying the concentration of each of the two substrates while keeping that of the other substrate constant, it was found
that the esterification reaction follows Michaelis-Menten kinetics. The surfactant-enzyme complex kinetic parameters were
determined with respect to both substrates. It was suggested that the kinetics of the lipase-catalyzed esterification reaction
model follow a Ping-Pong Bi Bi mechanism with no substrate or product inhibition. 相似文献
4.
Lipase-catalyzed transesterification of phosphatidylcholine at controlled water activity 总被引:2,自引:0,他引:2
Ingemar Svensson Patrick Adlercreutz Bo Mattiasson 《Journal of the American Oil Chemists' Society》1992,69(10):986-991
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. 相似文献
5.
J. Bezard G. Sempore G. Descargues A. Sawadogo 《European Journal of Lipid Science and Technology》1981,83(1):17-23
A method of determination of the 2-isomers of mixtures of triglycerides is proposed in this paper. This method has been applied to one class of triglycerides of peanut oil, fractionated by Argentation Thin-Layer Chromatography (Ag+-TLC), namely the class 012 (one saturated, one mono- and one diunsaturated fatty acid in the molecule), The calculation takes into account as experimental data, besides the fatty acid composition of monoglycerides issued from lipolysis by pancreatic lipase, the fatty acid composition of one class of diglycerides, fractionated by Ag+-TLC, either 01 or 02. It is shown that this method can be utilized even when the total diglycerides, issued from lipolysis, are not completely representative of the original triglycerides, due to preferential hydrolysis of unsaturated fatty acids at external positions of glycerol. As a matter of fact, the fatty acid composition of the different classes of diglycerides is not modified by this specific hydrolysis. Only is altered the relative proportion of the various classes of diglycerides. But the calculation utilized the proportion the class should have in the case of a non-preferential hydrolysis. It is easily calculated from the fatty acid composition of the mono-glycerides. Thus only the monoglycerides formed during lipolysis have to be representative of the original triglycerides. Resolution of a system of equations derived from the composition of monoglycerides and of one class of diglycerides (01) or the other one (02) has permitted the nature and the proportion of eighteen 2-isomers of the triglycerides 012 from peanut oil, to be precisely determined. The results show that the 2-position of glycerol is, in all cases, preferentially occupied by linoleic acid, and then by oleic acid. In this class of tri glycerides (012) palmito-linoleo-olein (16:0 - 18:2 - 18:1) re presents 37.2%, that is 5.2% of total peanut oil triglycerides. 相似文献
6.
Transesterification of oil by fatty acid-modified lipase 总被引:2,自引:0,他引:2
Mototake Murakami Yoshihiro Kawasaki Masami Kawanari Hideo Okai 《Journal of the American Oil Chemists' Society》1993,70(6):571-574
Fatty acid was covalently attached to lipase (EC 3.1.1.3.) fromPhycomyces nites, yielding a modified lipase of higher specific activity in hydrolytic and synthetic reactions in organic solvents. Attached
long-chain fatty acids solubilized the lipase in organic solvent and, therefore, promotion of dispersibility in organic solvent
resulted in much higher reactivity. The initial rate of transesterification by modified lipase was almost 40 times that of
native lipase in organic solvent. The specificities and selectivity of the modified lipase depended on the kind of attached
fatty acid. 相似文献
7.
A colorimetric determination of fatty acids as a new assay of lipases in reverse micelles 总被引:3,自引:0,他引:3
Peter Walde 《Journal of the American Oil Chemists' Society》1990,67(2):110-115
A new simple spectrophotometric method is described for the determination of the free fatty acid content in triglyceride oils
or other lipophilic samples. The method utilizes phenol red as fatty acid indicator, which is solubilized phenol red as fatty
acid indicator, which is solubilized in reverse micelles formed by AOT [sodiumbis(2-ethylhexyl) sulfosuccinate] in isooctane. Fatty acid determinations in vegetable oils can be carried out rapidly with oil
samples of less than 100 mg. The acid value of three different oils tested agreed quite well with the acid value obtained
for the same samples with another colorimetric determination using cupric acetate.
The method can be extended to a continuous determination of fatty acids which are released during the initial stage of a lipase
catalyzed hydrolysis of triglyceride substrates in reverse micelles. This new sensitive lipase assay has been applied for
a lipase ofPseudomonas bacteria with lipase concentrations as low as 0.1 μg/ml. Using trioctanoylglycerol as substrate in 50 mM AOT/isooctane with
wo=[H2O]/[AOT]=11.1 (pH 9.0), the apparent overall Michaelis-Menten constant (Km′app,ov) is 27 mM and the turnover number (kcat) 44 sec−1. 相似文献
8.
9.
Chandhapuram Mounika Sunki Yella Reddy 《Journal of the American Oil Chemists' Society》2012,89(9):1691-1697
Structured lipids containing behenic and medium chain (MC) fatty acids were prepared from palm stearin using 1,3-specific lipase-catalyzed acidolysis. Incorporation of MC and behenic acids was affected by proportion of substrate, type of fatty acids, reaction time, addition of water and quantity of lipase. It was found that incorporation of caproic acid was less compared to other longer chain fatty acids. Caprylic, capric and behenic acids shared similar incorporation (up to 32 %), which increased with the amount of fatty acids added and the time of reaction. The incorporation of these acids increased with addition of 1 % moisture and the increasing amount of enzyme from 5 to 10 % at the beginning of the reaction. Incorporating behenic and MC fatty acids, reduced palmitic and oleic acids considerably from palm stearin, the extent being the same as those incorporated. However, the reduction of linoleic acid was marginal. The solid fats content of the modified palm stearin containing MC and behenic acids were reduced at all temperatures due to a reduction in higher molecular weight triglycerides and an increasing proportion of lower chain triglycerides. The modified products of palm stearin with added capric and behenic acids were similar to commercial bakery shortenings and those with added capric acid were like salad or cooking oils or butter in melting characteristics. 相似文献
10.
Fatty acid monoesters of propylene glycol (1,2-propanediol) are good water-in-oil emulsifiers. These esters were synthesized
enzymatically to overcome the problems associated with chemical processes. APseudomonas lipase was added to reaction mixtures containing propylene glycol and various acyl donors (fatty acids, fatty acid ethyl
esters, fatty acid anhydrides and triglycerides) in organic solvents, and the mixtures were shaken at 30°C. The products were
analyzed by gas chromatography. The yield of monoesters was affected by the acyl donors, organic solvents, temperature, water
content, pH memory and reaction time. The anhydrous (lyophilized) enzyme and fatty acid anhydrides were best for monoester
production. The optimum pH ranges were 4–5 and 8–10. The yields of propylene glycol monolaurate, monomyristate, monopalmitate,
monostearate and monooleate with 50 mM fatty acid anhydrides as acyl donors were 97.2, 79.6, 83.7, 89.7 and 93.4 mM, respectively;
those with 50 mM fatty acids as acyl donors were 37.3, 28.7, 28.7, 35.3 and 36.2 mM, respectively. The yields of propylene
glycol monopalmitate, monostearate and monooleate with 50 mM triglycerides as acyl donors were 87.4, 65.1 and 83.2 mM, respectively. 相似文献
11.
This work proposes a lumped kinetic model for the acidolysis of a triacylglycerol (TAG) and an odd free fatty acid (FFA) in a non-aqueous medium, catalyzed by a 1,3 specific lipase immobilized on a solid support. This model is based on the mechanism of the acidolysis reaction by considering the following hypothesis: (1) only the fatty acids in positions 1 and 3 of TAG are exchanged and these two positions in the glycerol backbone are equivalent and (2) the only intermediate of appreciable lifespan in which the enzyme participates is the acyl-enzyme complex. The kinetic equation obtained for the rate of incorporation of an odd fatty acid to TAG has been applied to the results obtained in the acidolysis of three oils (commercial triolein, cod liver oil (CLO) and a commercial oil enriched in eicosapentaenoic acid (EPA), EPAX 4510TG) with caprylic acid (CA), catalyzed by the immobilized lipase Lipozyme IM contained in a packed bed reactor (PBR). The acidolysis has been carried out by recirculating the reaction mixture through the PBR until the reaction equilibrium was reached. In these conditions it has been proved that the PBR behaves as a perfect mixed dispersion reactor and the experimental results obtained at low TAG concentrations have been acceptably fitted to the kinetic expression obtained from the proposed model, with only two fitting parameters.However, for TAG concentrations higher than , an appreciable reduction of the reaction rate was observed. This result was due to the decrease of the effective diffusivity of reactants within the pores of the support where the lipase is immobilized, since the viscosity of the reaction mixture increases appreciably when the reactant concentration also does. When this phenomenon is included in the developed kinetic model, the experimental results obtained at high TAG concentrations could also be explained, even in absence of the organic solvent (n-hexane). It is observed that the influence of diffusion into the pores increases with the degree of CA incorporation to TAG, which was due to the increase of TAG and native fatty acid concentrations in the particle pores, which determines a continuous decrease in the effective diffusivity of CA. 相似文献
12.
Lipase-catalyzed modification of borage oil: Incorporation of capric and eicosapentaenoic acids to form structured lipids 总被引:2,自引:0,他引:2
Casimir C. Akoh Charment O. Moussata 《Journal of the American Oil Chemists' Society》1998,75(6):697-701
Two immobilized lipases, nonspecific SP435 from Candida antarctica and sn-1,3 specific IM60 from Rhizomucor miehei, were used as biocatalysts for the restructuring of borage oil (Borago officinalis L.) to incorporate capric acid (10:0, medium-chain fatty acid) and eicosapentaenoic acid (20:5n-3) with the free fatty acids
as acyl donors. Transesterification (acidolysis) reactions were carried out in hexane, and the products were analyzed by gas-liquid
chromatography. The fatty acid profiles of the modified borage oil were different from that of unmodified borage oil. Higher
incorporation of 20:5n-3 (10.2%) and 10:0 (26.3%) was obtained with IM60 lipase, compared to 8.8 and 15.5%, respectively,
with SP435 lipase. However, SP435 lipase was able to incorporate both 10:0 and 20:5n-3 fatty acids at the sn-2 position, but the IM60 lipase did not. Solvents with log P values between 3.5 and 4.5 supported the acidolysis reaction better than those with log P values between −0.33 and 3.0. 相似文献
13.
The acid lipase of castor bean endosperm catalyzed the hydrolysis of fatty acids from the 1 and 3 positions of synthetic glycerides
immediately after achieving proper reaction conditions, but fatty acids from the 2 position were not detected in the reaction
products until 7 to 10 min later. Results obtained with 2,3-butane dioleate, n-hexyl oleate and 2-hexyl oleate showed that
the castor lipase does not cleave secondary ester linkages. These findings suggest that the acid lipase of the castor bean
may catalyze hydrolysis of fatty acids from the 1 and 3 positions of triglycerides only; the steady appearance of 2 position
fatty acids in the reaction products during lipolysis is probably the result of an apparent isomerization reaction.
So. Utiliz. Res. Dev. Div., ARS, USDA. 相似文献
14.
Hongjie Ren Yang Li Wei Du Dehua Liu 《Journal of the American Oil Chemists' Society》2013,90(1):73-79
Free lipase-mediated alcoholysis for biodiesel production has drawn increasing attention in recent years due to its advantages of lower cost and faster reaction rate compared to immobilized lipase. Ethanol, derived from renewable biomass, has a great potential for biodiesel production. A previous study showed that free lipase NS81006 could effectively catalyze the ethanolysis of triglycerides for biodiesel preparation. Since most crude plant oils always contain an amount of free fatty acids, oleic acid was used as the model substrate for this study on lipase-mediated esterification for biodiesel production. The central composite design of the response surface methodology was adopted for process optimization. A biodiesel yield of over 90 % was achieved under optimal reaction conditions and the repeated use of the free lipase was easily realized through phase separation either by natural gravity force or centrifugation. 相似文献
15.
Sugar ester-modified lipase for the esterification of fatty acids and long-chain alcohols 总被引:1,自引:0,他引:1
Sobhi Basheer Mitsutoshi Nakajima Uri Cogan 《Journal of the American Oil Chemists' Society》1996,73(11):1475-1479
The esterification reaction of a long-chain fatty acid and a fatty alcohol with a surfactant-modified lipase in a microaqueousn-hexane system was studied. Various lipases from different sources were first modified with a surfactant of the sugar ester
type to improve their dispersibility in apolar organic solvents. This enzyme modification technique converted inactive crude
lipases to highly active biocatalysts for the esterification of long-chain fatty acids and fatty alcohols in a microaqueous
n-hexane system. The hydrophilic-lipophilic balance value and chainlength of the fatty acid residue of the fatty acid sugar
ester, used for modifying the lipases, significantly influenced the amount of precipitated lipase that was dissolved in the
aqueous solution, the protein content of the lipase-surfactant complex and its esterification activity. 相似文献
16.
Francesco Caponio Vincenzo Alloggio Cosimo Pallavicini 《European Journal of Lipid Science and Technology》1998,100(3):74-78
The lipid fraction of goat milk was subjected to transesterification using a commercially available immobilized lipase to decrease the amount of short- and medium-chain fatty acids (C4–C14) by enrichment of the reaction mixture with long-chain (C18:1 and C18:2) fatty acids. Aliquots were taken during, transesterification at different reaction times and analyzed for triglycerides and their fatty acid components. The gas chromatographic analyses of triglycerides (previously isolated by thinlayer chromatography) showed that at 6 h reaction under the experimental conditions led to the greatest reduction of the low molecular weight triglycerides (C22–C38) and concomitantly to the greatest increase in the higher molecular weight triglycerides (C48–C54). These changes correlated with the variations observed in the fatty acids of the triglyceride fraction. 相似文献
17.
A procedure is described for determining the stereospecific structure of triacid triglycerides containing oleic acid. The method utilizes the unique specificity of the lipase system fromGeotricum candidum for hydrolyzing fatty acids which containcis-9-unsaturation.The procedure involves a pancreatic lipase hydrolysis of 10-20 mg of substrate to determine the fatty acids in the beta-position and the incubation of another 50 mg of triglyceride withG. candidum lipase to obtain diglyceride for further treatment. The alpha,alpha- and alpha,beta-diglycerides are collected separately, converted to phenyl phosphatides and treated with phospholipase A. The analysis of the monoglycerides, produced with pancreatic lipase and the analysis of the beta-lysophosphatides allows the determination of the ratios of the original 2 position oleic acidsn-triglycerides while the analysis of the alpha-lysophosphatides aids in the determination of the originalsn-triglycerides which contained oleic acid in the 3 position. The 1 position oleic acidsn-triglycerides are calculated by difference.Racemic and enantiomeric triglycerides containing palmitic, stearic and oleic acids were synthesized and used to establish the limits of the new method. The good agreement between the actual and observed values for a mixture of isomers indicates that the procedure will be useful in the analysis of triacid triglycerides which contain oleic acid. The application of the procedure to triacid triglycerides which contain other unsaturated fatty acids is discussed. 相似文献
18.
Tatsuo Maruyama Shoji Umezaki Mitsutoshi Nakajima Minoru Seki 《European Journal of Lipid Science and Technology》2002,104(5):255-261
Native lipases often exhibit poor interesterification activity. We previously developed a fatty acid modification method to improve the activity of lipases. In this study, we applied this fatty acid modification method to several lipases and evaluated their interesterification and hydrolytic activities. The resulting interesterification activity was strongly dependent on the modifying fatty acid used. Of the saturated fatty acids tested, stearic acid modification substantially improved the interesterification activity of three lipases. Hydrolytic activity was affected slightly by the modifying fatty acid used. Substrate specificity of the modified lipase with triglycerides was also investigated and it was found that fatty acid modification changed the substrate specificity of some lipases. 相似文献
19.
Candida cylindracea lipase (SIGMA) was tested against triglycerides (TG) and wax esters (WE) of marine origin as substrates. Under the same conditions, wax esters were hydrolysed at a lower rate than the triglycerides. The C14 to C18 saturated and monounsaturated fatty acids were preferentially hydrolysed whereas the longer chain monoenes (20:1 and 22:1) and particularly the polyunsaturated fatty acids (18:4,20:5 and 22:6) were resistant to the hydrolysis in triglycerides as well as in wax esters. No specificity was demonstrated for the fatty alcohols in the wax esters. 相似文献
20.
Amidination of lipase with hydrophobic imidoesters 总被引:2,自引:0,他引:2
M. Basri K. Ampon W. M. Z. Yunus C. N. A. Razak A. B. Salleh 《Journal of the American Oil Chemists' Society》1992,69(6):579-583
Lipase fromCandida rugosa was chemically modified by amidination with imidoester hydrochlorides of different hydrophobicity. The modified enzyme showed
a higher ester synthesis activity but a lower ester hydrolysis activity compared with the native enzyme. The maximum specific
activity of the modified enzyme depended on its degree of derivatization. Benzene was found to be the best solvent for the
synthesis reaction. The optimal temperature for the reaction was not affected by modification of the lipase. The modified
lipase was more thermostable and solvent-stable than the native enzyme. When fatty acids of different carbon chainlength were
tested as substrates in the synthesis of esters with the modified lipase, the highest activity was observed with myristic
acid and propanol. 相似文献