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1.
A reliable, simultaneous analysis of palm oil polyol esters using capillary column GC is described. The polyol esters were
esterified from palm oil methyl esters (POME) and palm kernel oil methyl esters (PKOME) with trimethylolpropane [2-ethyl-2-(hydroxymethyl)-1,3-propanediol;
TMP] to produce the biodegradable base oil for lubricant production. Analysis was performed using a high-temperature capillary
column, SGE HT5 operated at a temperature gradient of 6°C/min starting from 80 to 340°C. Before injection, the sample was
derivatized with N,O-bis (trimethylsilyl)trifluoroacetamide in ethyl acetate at 40°C for at least 10 min. This procedure provides a complete separation
of reaction products: TMP, methyl esters, monoesters (ME), diesters (DE), and triesters (TE). As expected, the ME from palm
kernel oil was resolved into five major peaks, DE into seven peaks, and TE into 10 peaks. Since no standard was available
for this sample, the identities of the peaks were established by a secondary standard that was derived from pure methyl esters.
This GC method has made possible the simultaneous determination of reaction product compositions in order to assess the extent
of reaction. 相似文献
2.
In the presence of an immobilized lipase fromCandida antacrtica (Novozym 435R) fatty acids are converted to peroxy acids by the reaction with hydrogen peroxide. In a similar reaction, fatty acid esters
are perhydrolyzed to peroxy acids. Unsaturated fatty acid esters subsequently epoxidize themselves, and in this way epoxidized
plant oils can be prepared with good yields (rapeseed oil 91%, sunflower oil 88%, linseed oil 80%). The hydrolysis of the
plant oil to mono- and diglycerides can be suppressed by the addition of a small amount of free fatty acids. Rapeseed oil
methyl ester can also be epoxidized; the conversion of C=C-bonds is 95%, and the composition of the epoxy fatty acid methyl
esters corresponds to the composition of the unsaturated methyl esters in the substrate.
Based partly on a lecture at the 86th AOCS Annual Meeting & Expo, San Antonio, Texas, May 7–11, 1995. 相似文献
3.
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
4.
Robert R. Klein Gregory King Robert A. Moreau Gerald P. McNeill Pierre Villeneuve Michael J. Haas 《Journal of the American Oil Chemists' Society》1997,74(11):1401-1407
The fatty acid specificity and pH dependence of triacylglycerol hydrolysis by the Rhizopus delemar lipase acylbinding site mutant Val206Thr+Phe95Asp (Val, valine; Thr, threonine; Phe, phenylalanine; Asp, aspartic acid) were
characterized. The activity of the double mutant prolipase was reduced by as much as 10-fold, compared to the wild-type prolipase.
However, the fatty acid specificity profile of the enzyme was markedly sharpened and was dependent on the pH of the substrate
emulsion. At neutral pH, strong preference (10-fold or greater) for hydrolysis of triacylglycerols of medium-chainlength fatty
acids (C8:0 to C14:0) was displayed by the variant prolipase, with no hydrolysis of triacylglycerols of short-chain fatty acids (C4:0 to C6:0) and little activity manifested toward fatty acids with 16 or more carbons. At acidic pH values, the fatty acid selectivity
profile of the double mutant prolipase expanded to include short-chain triacylglycerols (C4:0, C6:0). When assayed against a triacylglycerol mixture of tributyrin, tricaprylin and triolein, the Val206Thr+Phe95Asp prolipase
displayed a high selectivity for caprylic acid and released this fatty acid at least 25-fold more efficiently than the others
present in the substrate mixture. When presented a mixture of nine fatty acid methyl esters, the wild-type prolipase showed
a broad substrate specificity profile, hydrolyzing the various methyl esters to a similar extent. Contrastingly, the double
mutant prolipase displayed a narrowed substrate specificity profile, hydrolyzing caprylic methyl ester at nearly wild-type
levels, while its activity against the other methyl esters examined was 2.5- to 5-fold lower then that observed for the wild-type
enzyme. 相似文献
5.
The procedure of the quantitative analysis of the components of sucrose ester products is described. By thin-layer chromatography, sucrose ester products have been separated into their components: mono-,di-,tri-, and higher esters. The individual components have been extracted from the plate and determined colorimetrically by using anthrone reagent. Standard substances of monoesters, diesters and triesters, which have been synthesized from gas-chromatographically pure methyl esters of fatty acids, have been isolated by column chromatography and identified by elemental analysis, colorimetric determination and N.M.R. determination. 相似文献
6.
In this paper a method is described for preparing 10 g or more of heptadecenoic acid (C17:1ω8) of 99 p.100 purity fromCandida tripicallis yeast. Three cycles of treatment, based on crystallization techniques, were used successively: (1) Crystallization of fatty
acids (in free form) from acetone at −25 C induced the elimination of most of the saturated fatty acids, and at −60 C, of
all of the poly-unsaturated acids. (2) Inclusion formation of fatty acids (as methyl esters) with urea at hC induced the removal
of all of the remaining saturated methyl esters and most of methyl oleate. (3) Crystallization of fatty acid methyl esters
from acetone at −60 C removed almost all the remaining monounsaturated methyl esters (methyl palmitoleate and methyl oleate).
Total efficiency of the preparation was about 17 p. 100. 相似文献
7.
Sugar fatty acid esters are surfactants that are widely used in food, cosmetics, and pharmaceutical industries. In this study, enzymatic production of d-sorbitol monoesters with various fatty acids (C10–C18) was assessed. Reactions were performed in tert-butanol at 40 °C, catalyzed by Candida sp. 99–125 lipase. Dissolution of the substrates was found to be the limiting step of the reaction, and hence preheating was performed to increase the solubility of d-sorbitol. Thus, the yield of d-sorbitol palmitate was increased from 7.34 to 31.6 mM. The results demonstrated that the specific lipase preferred long-chain fatty acids. The surface-active properties of the products were also determined. 相似文献
8.
Cecilia García-Oliva Almudena Perona ngel Rumbero Pilar Hoyos María J. Herniz 《International journal of molecular sciences》2022,23(4)
Rhamnolipids are becoming an important class of glycolipid biosurfactants. Herein, we describe for the first time the enzymatic synthesis of rhamnose fatty acid esters by the transesterification of rhamnose with fatty acid vinyl esters, using lipase from Pseudomonas stutzeri as a biocatalyst. The use of this lipase allows excellent catalytic activity in the synthesis of 4-O-acylrhamnose (99% conversion and full regioselectivity) after 3 h of reaction using tetrahydrofuran (THF) as the reaction media and an excess of vinyl laurate as the acyl donor. The role of reaction conditions, such as temperature, the substrates molar ratio, organic reaction medium and acyl donor chain-length, was studied. Optimum conditions were found using 35 °C, a molar ratio of 1:3 (rhamnose:acyldonor), solvents with a low logP value, and fatty acids with chain lengths from C4 to C18 as acyl donors. In hydrophilic solvents such as THF and acetone, conversions of up to 99–92% were achieved after 3 h of reaction. In a more sustainable solvent such as 2-methyl-THF (2-MeTHF), high conversions were also obtained (86%). Short and medium chain acyl donors (C4–C10) allowed maximum conversions after 3 h, and long chain acyl donors (C12–C18) required longer reactions (5 h) to get 99% conversions. Furthermore, scaled up reactions are feasible without losing catalytic action and regioselectivity. In order to explain enzyme regioselectivity and its ability to accommodate ester chains of different lengths, homology modelling, docking studies and molecular dynamic simulations were performed to explain the behaviour observed. 相似文献
9.
Summary Various preparations of sucrose fatty acid esters were hydrolyzed by wheat germ or pancreatic lipase, pancreatin, pancreatic
juice, α-amylase, invertase, or liver homogenates to yield sucrose and free fatty acids as products. The greatest activity
was observed with the liver homogenate.
None of the enzymes studied cleaved the glycosidic linkage as indicated by the lack of appearance of reducing groups and by
paper chromatography of the products.
The greatest hydrolysis by pancreatic lipase was observed with sucrose esters having a greater preponderance of unsaturated
fatty acids, namely, sucrose trilinoleate, sucrose dilinoleate, sucrose tetralinoleate, and “Sequol 260” (69% unsaturated
fatty acids).
Sodium taurocholate was required for hydrolysis by pancreatic lipase but not by wheat germ lipase. Sucrose ester was inhibitory
to the hydrolysis of triolein by all lipolytic preparations. Tetra-ethyl pyrophosphate and cupric ions were not inhibitory
to the hydrolysis of sucrose ester.
Sucrose fatty acid esters supported respiration by rat liver homogenates and to a much lesser extent by rat intestinal mucosa.
The rate of oxidation was greater than that observed with sucrose and the corresponding fatty acid. The greatest activity
was observed with esters of fatty acids having a greater preponderance of unsaturated fatty acids, namely, “Sequol 260,” sucrose
di-, tri-, and tetralinoleate.
This work was carried out under U.S.P.H.S. Grant No. A-1808 and Sugar Research Foundation Grant No. 109. 相似文献
10.
Chemo-enzymatic synthesis of disaccharide fatty acid esters 总被引:3,自引:0,他引:3
Douglas B. Sarney Herwig Kapeller Guiseppe Fregapane Evgeny N. Vulfson 《Journal of the American Oil Chemists' Society》1994,71(7):711-714
A novel enzymatic method for the synthesis of disaccharide fatty acid esters was developed with immobilizedMucor miehei lipase (Lipozyme IM-60; Novo Nordisk, Bagsvaerd, Denmark) as a catalyst. A range of lactose and maltose monoesters was prepared
in overall yields of 48–77% from the corresponding sugar acetals and fatty acids. 相似文献
11.
Enzymatic conversion of waste edible oil to biodiesel fuel in a fixed-bed bioreactor 总被引:9,自引:0,他引:9
Yomi Watanabe Yuji Shimada Akio Sugihara Yoshio Tominaga 《Journal of the American Oil Chemists' Society》2001,78(7):703-707
The conversion of waste edible oil to biodiesel fuel in a fixed-bed bioreactor was investigated. Three-step methanolysis of
waste oil was conducted using three columns packed with 3 g of immobilized Candida antarctica lipase. A mixture of waste oil and 1/3 molar equivalent of methanol against total fatty acids in the oil was used as substrate
for the first-step reaction, and mixtures of the first- and second-step eluates and 1/3 molar equivalent of methanol were
used for the second- and third-step reactions, respectively. Ninety percent of waste oil was converted to the corresponding
methyl esters (ME) by feeding substrate mixtures into the first, second, and third reactors at flow rates of 6, 6 and 4 mL/h,
respectively. We also attempted one-step methanolysis of waste oil. When a mixture of waste oil and 90% ME-containing eluate
(1∶3, wt/wt) and an equimolar amount of methanol against total fatty acids in the waste oil was fed into a reactor packed
with 3 g of immobilized C. antarctica lipase at a flow rate of 4 mL/h, the ME content in the eluate reached 90%. The immobilized biocatalyst could be used for
100 d in the two reaction systems without significant decrease in its activity. Waste oil contained 1980 ppm water and 2.5%
free fatty acids, but these contaminants had little influence on enzymatic production of biodiesel fuel. 相似文献
12.
Michael J. Haas Scott Bloomer Karen Scott 《Journal of the American Oil Chemists' Society》2000,77(4):373-379
We report a simple method that efficiently esterifies the fatty acids in soapstock, an inexpensive, lipid-rich by-product
of edible oil production. The process involves (i) alkaline hydrolysis of all lipid-linked fatty acid ester bonds and (ii)
acid-catalyzed esterification of the resulting fatty acid sodium salts. Step (i) completely saponified all glycerides and
phosphoglycerides in the soapstock. Following water removal, the resulting free fatty acid sodium salts were rapidly and quantitatively
converted to fatty acid methyl esters (FAME) by incubation with methanol and sulfuric acid at 35°C and ambient pressure. Minimum
molar reactant ratios for full esterification were fatty acids/methanol/sulfuric acid of 1∶30∶5. The esterification reaction
was substantially complete within 10 min and was not inhibited by residual water contents up to ca. 10% in the saponified soapstock. The product FAME contained >99% fatty acid esters, 0% triglycerides, <0.05% diglycerides,
<0.1% monoglycerides, and <0.8% free fatty acids. Free fatty acid levels were further reduced by washing with dilute sodium
hydroxide. Free and total glycerol were <0.01 and <0.015%, respectively. The water content was <0.04%. These values meet the
current specifications for biodiesel, a renewable substitute for petroleum-derived diesel fuel. The identities and proportions
of fatty acid esters in the FAME reflected the fatty acid content of soybean lipids. Solids formed during the reaction contained
69.1% ash and 0.8% protein. Their sodium content indicated that sodium sulfate was the prime inorganic component. Carbohydrate
was the predominant organic constituent of the solid. 相似文献
13.
Suresh Ramamurthi Prakash R. Bhirud Alan R. McCurdy 《Journal of the American Oil Chemists' Society》1991,68(12):970-975
Methylation of canola oil deodorizer distillate catalyzed by a nonspecific lipase was investigated. The conversion of fatty
acids to methyl esters has been optimized by using a statistical design. Up to 96.5% conversion of fatty acids to their methyl
esters has been achieved without the aid of vacuum or any water-removing agent. The effects of temperature, ratio of the reactants
(methanol: fatty acids in the deodorizer distillate) and enzyme concentration on the equilibrium conversion were studied.
The temperature and ratio of the reactants showed a significant effect on the conversion of fatty acids to methyl esters and
they exhibited a strong interactive effect. Enzyme concentration in the range of 2.7% to 4.3% did not show a significant effect
on the equilibrium conversion of fatty acids. Greater than 95% conversion of fatty acids to methyl esters was achieved at
temperatures around 50°C and at a ratio of the reactants between 1.8 and 2.0. The inhibitory effect of hydrophilic methanol
on the enzyme activity was largely reduced by working at the lower temperature range (around 50°C). 相似文献
14.
Yuji Shimada Yoshinori Hirota Takashi Baba Akio Sugihara Shigeru Moriyama Yoshio Tominaga Tadamasa Terai 《Journal of the American Oil Chemists' Society》1999,76(6):713-716
Steryl esters of long-chain fatty acids have water-holding properties, and polyunsaturated fatty acids (PUFA) have various
physiological functions. Because steryl ester of PUFA can be expected to have both features, we attempted to synthesize steryl
esters of PUFA by enzymatic methods. Among lipases used, Pseudomonas lipase was the most effective for the synthesis of cholesteryl docosahexaenoate. When a mixture of cholesterol/docosahexaenoic
acid (3:1, mol/mol), 30% water, and 3000 units/g of lipase was stirred at 40°C for 24 h, the esterification extent attained
89.5%. Under the same reaction conditions, cholesterol, cholestanol, and sitosterol were also esterified efficiently with
docosahexaenoic, eicosapentaenoic, arachidonic, and γ-linolenic acids. 相似文献
15.
Teodora Kocsisov Jozsef Juhasz Jn Cvengro 《European Journal of Lipid Science and Technology》2006,108(8):652-658
Hydrolysis of esters of higher fatty acids by subcritical water, performed in a flow‐through tubular reactor, was investigated at temperatures from 280 up to 340 °C and pressures exceeding 12 MPa, using an ester/water ratio of 1 : 2 or 1 : 4 (vol/vol). The kinetics of the hydrolysis of both the triacylglycerols and the methyl esters obeyed the rate equation valid for first‐order reactions. Conversion of the esters to free fatty acids exceeding 95% was reached at the temperature of 340 °C during 12 min. IR spectroscopy revealed structural changes in the chains of the unsaturated fatty acids and their partial polymerization during the hydrolysis. 相似文献
16.
J. J. Ellington P. F. Schlotzhauer A. I. Schepartz 《Journal of the American Oil Chemists' Society》1978,55(7):572-573
Flue-cured tobacco was subjected to alkaline hydrolysis, and, after acidification, the fatty acids and nonsaponifiables were
extracted into hexane. Treatment of the hexane extract with diazomethane yielded fatty acid methyl esters. The methyl esters
were separated from interfering hydrocarbons and sterols by preparative thin layer chromatography (PTLC). After addition of
an internal standard, the esters were quantitated by gas chromatography on the column packing, Silar 10C. Quantitation of
the C14-C32 fatty acid esters was possible by means of temperature programming. 相似文献
17.
Yomi Watanabe Yuji Shimada Akio Sugihara Hideo Noda Hideki Fukuda Yoshio Tominaga 《Journal of the American Oil Chemists' Society》2000,77(4):355-360
Candida antarctica lipase is inactivated in a mixture of vegetable oil and more than 1∶2 molar equivalent of methanol against the total fatty
acids. We have revealed that the inactivation was eliminated by three successive additions of 1∶3 molar equivalent of methanol
and have developed a three-step methanolysis by which over 95% of the oil triacylglycerols (TAG) were converted to their corresponding
methyl esters (ME). In this study, the lipase was not inactivated even though 2∶3 molar equivalent of methanol was present
in a mixture of acylglycerols (AG) and 33% ME (AG/ME33). This finding led to a two-step methanolysis of the oil TAG: The first-step
was conducted at 30°C for 12 h with shaking in a mixture of the oil, 1∶3 molar equivalent of methanol, and 4% immobilized
lipase; the second-step reaction was done for 24 h after adding 2∶3 molar equivalent of methanol (36 h in total). The two-step
methanolysis achieved more than 95% of conversion. When two-step reaction was repeated by transferring the immobilized lipase
to a fresh substrate mixture, the enzyme could be used 70 cycles (105 d) without any decrease in the conversion. From the
viewpoint of the industrial production of biodiesel fuel production, the two-step reaction was conducted using a reactor with
impeller. However, the enzyme carrier was easily destroyed, and the lipase could be used only several times. Thus, we attempted
flow reaction using a column packed with immobilized Candida lipase. Because the lipase packed in the column was drastically inactivated by feeding a mixture of AG/ME33 and 2∶3 molar
equivalent of methanol, three-step flow reaction was performed using three columns packed with 3.0 g immobilized lipase. A
mixture of vegetable oil and 1∶3 molar equivalent of methanol was fed into the first column at a constant flow rate of 6.0
mL/h. The eluate and 1∶3 molar equivalent of methanol were mixed and then fed into the second column at the same flow rate.
The final step reaction was done by feeding a mixture of eluate from the second column and 1∶3 molar equivalent of methanol
at the same flow rate. The ME content in the final-step eluate reached 93%, and the lipase could be used for 100 d without
any decrease in the conversion. 相似文献
18.
Najla Postaue Bruna Tais Ferreira de Mello Lúcio Cardozo‐Filho Camila da Silva 《European Journal of Lipid Science and Technology》2020,122(6)
Methyl esters (ME) and triacetin production from the supercritical interesterification of the product from low pressure extraction (crambe seed oil and methyl acetate) are evaluated. Reactions are conducted at 300–375 °C for different residence times, at 20 MPa, and under these conditions the thermal stability of triacetin is evaluated. The effect of the free fatty acid (FFA) concentration (in oil) is determined. An increase in temperature favors the formation of ME and triacetin at shorter reaction times. At 375 °C, after 15 min a drop in the ME yield is observed and triacetin is not detected. A reduction in the triacetin concentration (reaching ≈99%) is observed at 375 °C. High FFA concentration (in oil) initially provided higher product generation, however, after 15 min no influence is observed. The highest ME yield (≈60%) is obtained at 300 °C, along with 1.22 wt% triacetin and ≈5.0 wt% unreacted compounds. Practical Applications: This paper reports new experimental data on an integrated process for the production of methyl esters from low pressure extraction (crambe seeds and methyl acetate) and supercritical reaction of the extraction mixture. The technique used allows the removal of a high quantity of oil from good quality crambe seeds. The viability of applying the integrated process to obtain oils with a high content of free fatty acids is verified, promoting the obtainment of relatively simple methyl esters. The procedure does not require oil purification and solvent recovery prior to the reaction. 相似文献
19.
Propylene glycol monoesters (PGM) of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are potentially health-beneficial
water-in-oil emulsifiers useful in the food industry. These esters were synthesized enzymatically to overcome the problems
associated with chemical processes. The products were analyzed by gas chromatography. The immobilizedMucor miehei lipase was found to be the best enzyme for the synthesis of both propylene glycol monoesters of EPA and DHA among nine lipases
tested. The anhydrous enzyme and hydrophobic organic solvents were favored for the production of both monoesters. The yields
of monoesters were also affected by temperature, pH memory, fatty acid/propylene glycol ratio, and reaction time. The yields
of PGMDHA and PGMEPA with 50 mM fatty acid and 225 mM propylene glycol as substrates in 1 mL solvent mixture (hexane/t-butyl alcohol=9:1), catalyzed by Lipozyme IM-20 (50 mg) at 40°C for 24 h, were 47 and 49 mM, respectively. The enzyme still
retained over 60% of its original activity after 10 d of batch-type operation (1 d per cycle) at 40°C for the synthesis of
both PGMDHA and PGMEPA. 相似文献
20.
Recycled vegetable oil (RVO) is a relatively cheap raw material for biodiesel production, but biodiesel grade methyl ester
yields from RVO were found to be considerably lower than those from pure plant oil. The present paper investigates sources
of yield loss during methanolysis of RVOs with free fatty acids (FFA) contents of 0.4–3.3%, and makes suggestions for the
improvement of methyl ester yields. Data presented here indicated that yield losses of methyl esters during methanolysis were
due to triglyceride and methyl ester hydrolysis and to the dissolution of methyl esters in the glycerol phase. Hydrolysis
of triglycerides and methyl esters seemed to be the only side reaction causing yield losses, and the amount of fatty acids
from hydrolysis increased with concentration of the potassium hydroxide catalyst. Dissolution of methyl esters in the glycerol
phase was probably caused by the detergent effect of potassium salts of fatty acids originating from FFA in the RVO and from
triglyceride hydrolysis, and the amount of dissolved methyl esters increased with FFA content of the RVO. The FFA content
of the RVO had no effect on hydrolysis, and the amount of triglycerides and methyl esters hydrolysed during methanolysis remained
constant with increasing FFA content of the RVO. 相似文献