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1.
Douglas G. Hayes Robert Kleiman 《Journal of the American Oil Chemists' Society》1995,72(11):1309-1316
Eight lipases were screened for their ability to synthesize estolides from a mixture that contained lesquerolic (14-hydroxy-11-eicosenoic)
acid and octadecenoic acid. With the exception ofAspergillus niger lipase, all 1,3-specific enzymes (fromRhizopus arrhizus andRhizomucor miehei lipases) were unable to synthesize estolides.Candida rugosa andGeotrichum lipases catalyzed estolide formation at >40% yield, with >80% of the estolide formed being monoestolide from one lesquerolic
and one octadecenoic acyl group:Pseudomonas sp. lipase synthesized estolides at 62% yield, but the product mixture contained significant amounts of monoestolide with
two lesquerolic acyl groups as well as diestolide. ImmobilizedR. miehei lipase was chosen to catalyze the esterification of mono-and polyestolide, derived synthetically from oleic acid, with fatty
alcohols or α,ω-diols. Yields were >95% for fatty alcohol reactions and >60% for diol reactions. In addition, the estolide
linkage remained intact through the course of the esterification process. Esterification of estolides improved the estolide’s
properties—for example, lower viscosity and higher viscosity index—but slightly raised the melting point. Estolides and, particularly,
estolide esters may be suitable as lubricants or lubricant additives. 相似文献
2.
Lipase-catalyzed alcoholysis of soy phospholipids was investigated to simultaneously make lysophospholipids and fatty acid
esters of individual alcohols. Alcoholysis was carried out by stirring a mixture of soy phospholipids and individual alcohols
in equimolar proportions with 10% (by weight of reactants) Mucor miehei lipase at 55°C for 24 h. The products were isolated by column chromatography after removal of the lipase. Lysophospholipids
(in 69–78% molar yield) were obtained from soy phospholipids, and the yield of esters of various alcohols also conformed nearly
with theoretical yields. 相似文献
3.
The influence of acid/polyol molar ratio and reaction time on lipase-catalyzed esterification of oleic acid (OA) and sorbitol
was studied to determine optimal conditions for monoester synthesis. A simple mathematical model was developed to determine
relationships between various parameters of technical and/or economical importance. A direct relationship. independent of
OA initial concentration and reaction time, was shown between the percentage of monoester in total esters, monoester concentration
(the maximum was 25–30 mM for 70–80% monoester), and sorbitol conversion rate. A high sorbitol conversion was always associated
with a low percentage of monoester in total ester. No absolute optimum could be found, so that compromises should be chosen,
with the help of the results presented herein, depending on the constraints on the process. Two possible optima are proposed.
In both examples, monoester (25–30 mM) is 80% pure. In the first case, productivity is maximized (15 mmol·L−1·h−1), but OA and sorbitol conversions are only 40 and 60%, respectively. In the second case, a high OA conversion (>99%) is favored
at the expense of monoester productivity (1.8 mmol·L−1·h−1), 60% of the sorbitol being converted. It was shown that, although sorbitol monoester has better surface properties than
diester, the addition of 20% diester did not modify the interfacial activity of monoester and slightly increased its surface
activity. 相似文献
4.
Marta Martinez-Garcia Winnie Dejonghe Lieve Cauwenberghs Miranda Maesen Karolien Vanbroekhoven Yamini Satyawali 《European Journal of Lipid Science and Technology》2021,123(2):2000225
Glucose- and xylose laurate esters are enzymatically synthesized using equimolar substrate concentrations in 2-methyl-2-butanol, comparing free lauric acid with methyl- and vinyl-laurate as acyl donors. All reactions result in ≥70% acyl donor conversions after 72 h but the activated donors are also partially hydrolyzed to lauric acid, highlighting the difficulty in controlling water presence in this particular reaction system. The esterification of xylose generates a complex product profile, with several regioisomers of monoesters and diesters. The esterification of glucose is quite selective, forming mainly the 6-O monoester (≥96%) with a small presence of two diester isomers (4%). Increasing substrate concentration up to 800 millimoles kg−1 results in lower conversion values (down to 58%) but shows that the reaction proceeds successfully even in the presence of high amounts of insoluble glucose. However, the reaction is less selective and the proportion of diester increases, becoming up to 46% (molar fraction) of the final product. Solvent recovery after esterification can be achieved by organic solvent nanofiltration through a polymeric membrane able to retain ≥80% of all reaction substrates and products. Practical Applications: The use of high substrate concentrations during the enzymatic synthesis of sugar ester biosurfactants leads to product titers that are more industrially appealing, without the need to find a solvent that can solubilize all initial substrate. The sustainability of the enzymatic conversion at mild temperatures can be enhanced by recycling of the reaction solvent through organic solvent nanofiltration, an energy efficient alternative to other traditional methods like distillation. 相似文献
5.
Giuseppe Fregapane Douglas B. Sarney Sydney G. Greenberg Dorothy J. Knight Evgeny N. Vulfson 《Journal of the American Oil Chemists' Society》1994,71(1):87-91
5-O-Acyl-1,2-O-isopropylidene-D-xylofuranose and 6-O-acyl1,2∶3,4-di-O-isopropylidene-D-galactopyranose were enzymatically prepared from the corresponding monosaccharide acetals and commercial
(crude) fatty acid mixtures. Subsequent acid-catalyzed hydrolysis of the isopropylidene group(s) gave monosaccharide esters
with overall yields of 59–88%, where the monoester content was at least 80% (galactose oleate) and typically 90% for the other
preparations. In contrast to sugar fatty acid esters prepared by conventional, high-temperature (trans)esterification, the
enzymatically obtained monosaccharide esters contained no appreciable quantities of undersirable side products, and the only
contaminants were monosaccharides and fatty acids. 相似文献
6.
Substrate preferences for lipase-mediated acyl-exchange reactions with butteroil are concentration-dependent 总被引:1,自引:0,他引:1
Substrate preferences for pancreatic lipase-mediated acyl-exchange reactions with butteroil were concentration-dependent for
the series of acyl donors and alcohol acceptors evaluated. For acidolysis reactions, the initial reaction rates and percent
reaction yields after 18 h at 50 μmol acyl donor per gram substrate mixture were similar forn-fatty acids and their methyl and glycerol esters. At 400–500 μmol g−1 (and greater), order of initial reaction rates and percent reaction yield was fatty acid glycerol esters > fatty acid methyl
esters > fatty acids. At concentrations above 300–500 μmol g−1, reaction inhibition was observed for fatty acid substrates, and inhibition took place at lower concentrations for the shorter-chainlength
fatty acids of those evaluated (5–17 carbons). Inhibition was primarily attributed to acidification of the microaqueous environment
of the lipase. Desorption of water by the fatty acid substrate may be a secondary mode of inhibition. The concentration dependence
of initial reaction rates and percent reaction yield was similar for then-alcohol substrates evaluated (2–15 carbons) for alcoholysis reactions with butteroil. Optimum alcohol concentration was 375–500
μmol g−1 (except for butanol, which was 1 mmol g−1, above which reaction inhibition was observed. Inhibition was attributed to desorption of water from the enzyme by the alcohol
substrate. Relative reactivity of classes of alcohols for this reaction system was primary alcohols > secondary alcohols >
tertiary alcohols. Generally, alcoholysis reactions were faster than acidolysis reactions, and triacylglycerols were the best
substrates for acidolysis reactions with butteroil at high levels (up to 2 mmol g−1) of acyl donor substrate. 相似文献
7.
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
8.
Tatsuo Yamamura Takafumi Ishida Hiroyuki Tatara Tomihiro Nishiyama 《Journal of the American Oil Chemists' Society》1997,74(6):739-744
We evaluated the antioxidant activities of 9H-xanthene-2,7-diols and α-tocopherol (α-Toc) upon the oxidation of soybean phosphatidylcholine liposomal membranes, induced
by 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) and 2,2′-azobis(2,4-dimethylvaleronitrile (AMVN). The stoichiometric
factors of 9H-xanthene-2,7-diols, initiated with water-soluble AAPH and lipid-soluble AMVN, were 1.9–2.7 and 1.2–1.8-fold greater than
those of α-Toc, respectively. The consumption profile of the antioxidant confirmed that 9H-xanthene-2,7-diol was completely consumed within the induction period (t
inh) and that the 9H-xanthene-2,7-diol oxidation product was formed. When all oxidation product was depleted, t
inh was terminated, and rapid oxidation occurred. These results suggested that the antioxidant activities of 9H-xanthene-2,7-diol depend not only on the initial hydrogen abstraction from 9H-xanthene-2,7-diol but also on a second hydrogen abstraction from the residual phenolic OH group of the oxidation product.
Ascorbic acid (AsA) could not scavenge the radicals by itself in the lipid bilayer. However, when 9H-xanthene-2,7-diol was located in the lipid bilayer, the addition of AsA into the aqueous phase prolonged t
inh and reduced the rate of decay of 9H-xanthene-2,7-diol. 相似文献
9.
Teruhisa Satsuki Kenji Umehara Yuji Yoneyama 《Journal of the American Oil Chemists' Society》1992,69(7):672-677
The detergency properties of α-sulfonated fatty acid methyl esters (α-SFMe) were evaluated and compared to those of conventional
anionic surfactants by using a model heavy-duty detergent formulation. Several physicochemical properties of surfactants were
measured to investigate the effective factors on detergency. α-SFMe showed good detergency performance under various washing
conditions. These results were considered to correlate well with the good adsorption behavior on oils and dispersing capabilities
for particles, as well as with the good solubilization capacity. Solubilization behavior of α-SFMe is discussed in relation
to micelle properties. It is suggested that α-SFMe can form suitable micelles for solubilizing polar oils advantageously,
due to its bulky hydrophilic group. 相似文献
10.
Hydroxy fatty acid (HFA) esters of long-chain alcohols, such as hydroxy stearates, have potential applications from lubricants
to cosmetics. These esters were synthesized enzymatically to overcome the problems associated with chemical processes. An
immobilized lipase, Rhizomucor miehei, was employed as catalyst in the esterification reaction between hydroxy-stearic acid as a source of HFA and monohydric fatty
alcohols (C8–C18). The yields of esters were in the range of 82–90% by conducting the reactions at 65±2°C, 2–5 mm Hg pressure, and 10% lipase
concentration. The products were analyzed by infrared spectroscopy, and some of their analytical characteristics were determined. 相似文献
11.
Tatsuo Yamamura Masaki Arashima Kazumi Nakatani Takafumi Ishida Fukiko Yamada Tomihiro Nishiyama 《Journal of the American Oil Chemists' Society》1995,72(4):497-500
The antioxidant activities of 9H-xanthene-2,7-diols and α-tocopherol were studied during the oxidation of linoleic acid in a homogeneous solution and in an
aqueous micelle dispersion. The antioxidant activities of 9H-xanthene-2,7-diols for both systems were 1.0–2.4 times greater relative to α-tocopherol. In addition, the 1,3,4,5,6,8-hexamethylxanthene-2,7-diol
showed less cytotoxicity toward human fibroblasts than did 2,6-di-t-butyl-4-methylphenol. 相似文献
12.
T. Okano J. Tanabe M. Fukuda M. Tanaka 《Journal of the American Oil Chemists' Society》1992,69(1):44-46
The surface-active properties and emulsification ability of sodium α-sulfonated fatty acid esters, CmH2m+1CH-(SO3Na)COOCnH2n+1, were studied as a function of the hydrophobic alkyl chainlength in the fatty acid (m=8−16) and the alcohol (n=8−18). As
a result, it was discovered that sodium α-sulfonated fatty acid esters have a structural effect on the Krafft point different
from that of amphiphiles with short alkyl chains. Moreover, some of the α-sulfonated fatty acid esters have quite low interfacial
tensions, as well as non-foaming properties, which depend upon the total (m+n) number of carbon atoms in the alkyl chains. 相似文献
13.
Through proper selection of initial conditions and control of the reaction medium composition, a productivity rate over 10-fold
higher than that previously reported was achieved for lipase-catalyzed fructose-oleic acid esterification. From a screening
process, tert-butanol (t-BuOH) was selected as the most effective solvent for cosolubilizing fructose and oleic acid during the initial stage of the
reaction. A t-BuOH concentration of 0.35–0.55 w/w produced the highest rate and extent of reaction at 60°C. Neither water addition nor
removal applied to initial reaction materials improved the rate. Since both fructose-oleic acid mono- and diester promoted
higher fructose solubility than either oleic acid or oleic acid/t-BuOH mixtures, t-BuOH was not needed during the latter stage of the reaction. Also, the presence of t-BuOH hindered the removal of water by free evaporation. Thus, complete removal of t-BuOH during the middle-to-latter stage of reaction was found to enhance the reaction rate. In addition, the introduction
of fructose to the reactor in small batchwise increments accelerated the reaction. The monoester to diester ratio decreased
during the initial and middle stages of the reaction owing to the disappearance of t-BuOH, but increased slightly during the later stages presumably because of the ester formation. 相似文献
14.
Volker Spitzer Werner Tomberg Mônica Zucolotto 《Journal of the American Oil Chemists' Society》1996,73(5):569-573
Besides some usual fatty acids, the seed oil ofSabastiana brasiliensis (Euphorbiaceae) contains up to 39% (estimated by ultraviolet spectroscopy) of α-parinaric acid (cis, trans, trans, cis-9, 11, 13, 15-octadecatetraenoic acid). The fatty acids were analyzed by gas chromatography and gas chromatography/mass spectrometry
as their methyl esters. The structure of α-parinaric acid was proven by a combination of chemical and spectroscopic methods,
conducted with the crude oil, the methyl ester mixture, and the isolated fatty acid methyl ester. Complete assignment of the1H and13C nuclear magnetic resonance (NMR) shifts of α-parinaric acid was carried out by two-dimensional NMR experiments
Presented in part at the 21st world Congress and Exhibition of the International Society for Fat Research (ISF), October 1–6,
1995, The Hague, The Netherlands. 相似文献
15.
Inhibitory Effect of Conjugated α-Linolenic Acid from Bifidobacteria of Intestinal Origin on SW480 Cancer Cells 总被引:1,自引:0,他引:1
Mairéad Coakley Sebastiano Banni Mark C. Johnson Susan Mills Rosaleen Devery Gerald Fitzgerald R. Paul Ross Catherine Stanton 《Lipids》2009,44(3):249-256
In this study, we assessed the ability of six strains of bifidobacteria (previously shown by us to possess the ability to
convert linoleic acid to c9, t11-conjugated linoleic acid (CLA) to grow in the presence of α-linolenic acid and to generate conjugated isomers of the fatty
acid substrate during fermentation for 42 h. The six strains of bifidobacteria were grown in modified MRS (mMRS) containing
α-linolenic acid for 42 h at 37 °C, after which the fatty acid composition of the growth medium was assessed by gas liquid
chromatography (GLC). Indeed, following fermentation of one of the strains, namely Bifidobacterium breve NCIMB 702258, in the presence of 0.41 mg/ml α-linolenic acid, 79.1% was converted to the conjugated isomer, C18:3 c9, t11, c15 conjugated α-linolenic acid (CALA). To examine the inhibitory effect of the fermented oils produced, SW480 colon cancer
cells were cultured in the presence of the extracted fermented oil (10–50 μg/ml) for 5 days. The data indicate an inhibitory
effect on cell growth (p ≤ 0.001) of CALA, with cell numbers reduced by 85% at a concentration of 180 μM, compared with a reduction of only 50% with
α-linolenic acid (p ≤ 0.01). 相似文献
16.
Matthew J. Hills Irmgard Kiewitt Kumar D. Mukherjee 《Journal of the American Oil Chemists' Society》1990,67(9):561-564
Immobilized lipase preparations from seedlings of rape (Brassica napus L.) andMucor miehei (lipozyme) used as biocatalysts in esterification and hydrolysis reactions discriminate strongly against γ-linolenic and
docosahexaenoic acids/acyl moieties. Utilizing this property, γ-linolenic acid contained in fatty acids of evening primrose
oil has been enriched seven to nine-fold, from 9.5 to almost 85% by selective esterification of the other fatty acids with
butanol. Similarly, docosahexaenoic acid of cod liver oil has been enriched four to five-fold, from 9.4 to 45% by selective
esterification of fatty acids (other than docosahexaenoic acid) with butanol. As long as the reaction is stopped before reaching
equilibrium, very little of either γ-linolenic acid or docosahexaenoic acid are converted to butyl esters, which results in
high yields of these acids in the unesterified fatty acid fraction. 相似文献
17.
Esters of carboxylic acids including 2-methylhexanoic, 2-methylbutyric, 2,2-dimethyl-4-pentenoic, palmitic, and oleic acids
were tested as substrates in methoxide-catalyzed interesterification and transesterification. The aliphatic acid esters participated
in the ester-ester interchange upon addition of catalytic sodium methoxide. Their isopropyl esters also produced methyl esters
on heating with sodium methoxide. The esters of α-methyl-substituted acids did not participate in the ester-ester interchange.
Their isopropyl esters did not react with methoxide to produce methyl esters. However, upon addition of methanol with sodium
methoxide, their methyl esters were produced. These results indicate that the first step in interesterification is possibly
that methoxide abstracts the α-hydrogen of an ester to form a carbanion. Interesterification is then likely completed via a Claisen condensation mechanism involving the β-keto ester anion as the active intermediate. The β-keto ester anion contains
positively charged ketone and acyl carbons that are active sites for nucleophilic attack by anions such as methoxide and glycerinate,
which would produce a methyl ester or rearrange acyls randomly. On the other hand, transesterification is a nucleophilic substitution
by methoxide at the acyl carbon in the presence of methanol. 相似文献
18.
A fractionally distilled C14−C16 fatty acid methyl ester, derived from palm oil, was sulfonated with gaseous SO3 in a falling film reactor to form an α-sulfo fatty acid methyl ester (α-SF; unbleached and unneutralized form). The included
dark-colored impurities were then separated from α-SF as a diethyl ether-insoluble matter. After purification by thin-layer
chromatography, the colored species were analyzed by ion-exchange chromatography, gel-permeation chromatography, and nuclear
magnetic resonance spectrometry. These data suggested that the colored species were polysulfonated compounds with conjugated
double bonds. Minor components in the raw fatty acid methyl ester, found by gas chromatography/mass spectrometry, were spiked
into the purified methyl palmitate and then sulfonated. The unsaturated methyl ester and hydroxy ester showed the worst color
results. The methyl oleate and methyl 12-hydroxystearate were then sulfonated and analyzed. Deep black products were obtained,
which showed the same properties as the colored species in α-SF. It was concluded that low levels of unsaturated fatty acid
methyl esters and hydroxy esters in the fatty acid methyl ester are the main causes of the coloring. 相似文献
19.
Oxidation kinetics of β-carotene in oleic acid solvent with addition of an antioxidant, α-tocopherol
Shibasaki-Kitakawa Naomi Kato Hideto Takahashi Atsushi Yonemoto Toshikuni 《Journal of the American Oil Chemists' Society》2004,81(4):389-394
Oxidation experiments with β-carotene were performed in oleic acid solvent with addition of an antioxidant, α-tocopherol.
A kinetic model was proposed based on a reaction mechanism consisting of the oxidation of β-carotene, oleic acid, and α-tocopherol;
the antioxidation reactions of β-carotene and oleic acid by α-tocopherol; the cross-reaction of β-carotene and oleic acid;
and the radical-exchange reaction of β-carotene and α-tocopherol. The model quantitatively described the oxidation behavior
of β-carotene over a wide range of temperatures, oxygen compositions, and initial antioxidant concentrations. The model simulated
well the time over which β-carotene was almost totally consumed under practical storage conditions at room temperature in
air. 相似文献
20.
Transesterification of cocoa butter by fungal lipases: Effect of solvent on 1,3-specificity 总被引:1,自引:0,他引:1
Transesterification and alcoholysis reactions catalyzed by immobilized lipases fromMucor miehei andHumicola lanuginosa in hexane gave fatty acid esters that did not reflect the expected 1,3-specificity of the enzymes, due to competing acyl
migrations in the partial glyceride products. However, both lipases were 1,3-specific in reactions when diethyl ether was
used as a solvent, and this provided a convenient analytical methodology in combination with gas chromatography and nuclear
magnetic resonance spectroscopy for the determination of fatty acid distribution within triglycerides. 相似文献