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1.
Pseudomonas sp. lipase (PS) was immobilized by adsorption technique onto glass beads and tested for its ability to synthesize geranyl
acetate by transesterification with acetic anhydride as the acyl donor. Reactions were carried out inn-hexane containing 0.1 M geraniol, 0.1 M acetic anhydride, and 200 units of lipase PS. Enzyme load, effect of substrate concentration,
added water, temperature, time course, organic solvent, pH memory, and enzyme reuse were studied. Yields of up to 96% were
obtained with 200 units (approximately 11% w/w of reactants) of enzyme. Increasing amounts of geraniol inhibited lipase activity,
while excess acyl donor concentration enhanced ester production. Yields as high as 97% were obtained at 50°C, 24 h incubation,
with no added water. Solvents with logP values ≥3.0 showed the highest conversion yields. Solvent-free samples also performed well. The pH range of 4–9 gave good
yields (92–98.4%). Enzyme reuse studies showed the lipase remained active after 15 runs. 相似文献
2.
Geranyl acetate is an important flavor and fragrance compound. Two immobilizedCandida antarctica lipases, SP382 and SP435, were investigated for their use in the synthesis of geranyl acetate by direct esterification. Yields
between 95 and 99% molar conversion were obtained with 2 and 15% (w/w reactants) of SP435 and SP382 lipases, respectively.
Optimum yields were obtained at 0.1M acetic acid and 0.12M geraniol after 16-h incubation. No inhibitory effect was observed
at increasing concentrations of geraniol. Addition of 60% (w/w reactants) water led to 50 and 60% reduction in the esterification
activity of SP382 and SP435 lipases, respectively. The best yields were obtained at added water contents between 0–5% (w/w
reactants). Solvents with a logP value of 0.85 or more gave reaction yields of more than 80% molar conversion. Higher logP values did not necessarily lead to higher conversion yields. The immobilized lipase SP382 was still active after reusing
ten times in the direct esterification reaction. 相似文献
3.
Lisa N. Yee Casimir C. Akoh Robert S. Phillips 《Journal of the American Oil Chemists' Society》1995,72(11):1407-1408
Pseudomonas sp. lipase was immobilized by adsorption onto five supports and tested for its ability to synthesize geranyl esters by transesterification
using short-chain triacylglycerols as acyl donors. Reaction mixtures were prepared in 2 mL ofn-hexane, 0.1 M geraniol, 0.03M triacylglycerol, and 200 units of lipase, and incubated at 30°C and 200 rpm for 24 h. Overall,
glass beads were the best support. Geranyl acetate and caproate performed best with Duolite (77.5 and 95.3%, respectively).
Geranyl butyrate and caprylate performed best with polyvinylpyrrolidone, (80.2 and 95.5%, respectively). Values for nonimmobilized
enzyme also were obtained. Immobilization improved yields, with geranyl caproate exhibiting best results. 相似文献
4.
The syntheses of geranyl acetate and citronellyl acetate by alcoholysis reaction catalyzed by immobilized lipase from Mucor miehei was studied for the first time in a solvent-free system. Reactions were carried out at a terpene alcohol/acyl donor molar
ratio of 1:5 with Lipozyme at 10% of the total weight of the reactants in a solvent-free system. Incubations were carried
out at 55 to 60°C for ethyl and butyl acetates as acyl donors, whereas for methyl acetate the incubation temperature was 40
to 45°C. Excess concentration of acyl donor increases the percentage of geranyl acetate and citronellyl acetate, while excess
of terpene alcohol concentration decreases the same. Yields from 75 to 77% molar conversion (90 to 98% conversion, w/w) were
obtained after 8 to 28 h of reaction time. 相似文献
5.
Response surface methodology (RSM) and a five-level-five-factor central composite rotatable design (CCRD) were used to evaluate
the effects of synthetic variables, such as reaction time (3 to 27 h), temperature (25 to 65 °C), enzyme amount (10 to 50%),
substrate molar ratio of citronellol to butyric acid (1∶1 to 1∶3), and added water amount (0 to 20%) on molar percent yield
of citronellyl butyrate by direct esterification, using lipase IM77 from Mucor miehei. Reaction time and temperature were the most important variables. Substrate molar ratio had no effect on percent molar conversion.
Based on contour plots, optimal synthetic conditions were these: reaction time 24 h, temperature 60°C, enzyme amount 20%,
substrate molar ratio 1∶1.5, and added water 0%. The predicted molar conversion value was 100%. An actual experimental value
of 98% molar conversion was obtained. 相似文献
6.
An immobilized sn-1,3-specific lipase from Rhizomucor miehei (IM 60) was used to catalyze the interesterification of tristearin (C18:0) and tricaprin (C10:0) to produce low-calorie structured lipids (SL). Acceptable product yields were obtained from a 1:1 mole ratio of both triacylglycerols
with 10% (w/w of reactants) of IM 60 in 3 mL hexane. The SL molecular species, based on total carbon number, were 44.2% C41 and 40.5% C49, with 3.8 and 11.5% unreacted tristearin C57 and tricaprin C27, respectively, remaining in the product mixture. The best yield of C41 species (44.3%) was obtained with zero added water. Tricaprylin (C8:0) was also successfully interesterified with tristearin in good yields at 1:1 mole ratio. Products were analyzed by reverse-phase
high-performance liquid chromatography with an evaporative light-scattering detector. Reaction parameters, such as substrate
mole ratio, enzyme load, time course, added water, reaction media, and enzyme reuse, were also investigated. Hydrolysis by
pancreatic lipase revealed the specific fatty acids present at the sn-1,3 positions of SL.
Biocatalysis Symposium Paper, presented at the AOCS Annual Meeting & Expo, Seattle, Washington. May 11–14, 1997. 相似文献
7.
Lipase from Candida antarctica was entrap-immobilized in cellulose acetate-TiO2 gel fiber (fiber-immobilized lipase) by the sol-gel method. Syntheses of geranyl acetate and citronellyl acetate catalyzed
by the fiber-immobilized lipase were studied in heptane solution. Conversions reached 85% for geranyl acetate after 100 h,
and 75% for citronellyl acetate after 80 h, and these values were almost identical to those for syntheses catalyzed by nonimmobilized
lipase, although the reaction rate was decreased by immobilization. Compared to those of the non-immobilized lipase and commercially
available immobilized lipase (Novozyme 435), the activity of the fiber-immobilized lipase was not particularly affected by
changes in reaction conditions, such as bulk water content or substrate concentration. The fiber-immobilized lipase retained
a high level of activity after six repeated uses, and almost no enzyme leakage from fiber was observed. However, the reactivity
of the fiber-immobilized lipase was depressed at higher temperature, presumably due to dehydration by thermal contraction
of the gel fiber. 相似文献
8.
B. K. De T. Chatterjee D. K. Bhattacharyya 《Journal of the American Oil Chemists' Society》1999,76(12):1501-1504
Synthesis of geranyl and citronellyl esters of mixed fatty acids has been investigated by alcoholysis of coconut oil (CNO)
using Rhizomucor miehei lipase. CNO fatty acid esters of geraniol and citronellol have unique mild flavors that can be used in food materials. Both
geraniolysis and citronellolysis of CNO produce flavor esters in good yield. Depending on substrate concentration the molar
yield is more than 50%. The optimized reaction conditions were: pressure, atmospheric; temperature, 50°C; incubation period,
5 h; and Lipozyme, 10% (w/w). 相似文献
9.
Continuous production of fatty acids from palm olein by immobilized lipase in a two-phase system 总被引:1,自引:0,他引:1
Aran H-Kittikun Poonsuk Prasertsan Chatchai Sungpud 《Journal of the American Oil Chemists' Society》2000,77(6):599-603
Commercial lipases were tested for the ability to hydrolyze palm olein in isooctane in a two-phase system. Lipase OF (from
Candida rugosa) showed the highest specific activity of 209 U/mg protein where 1 U is the amount of lipase enzyme required to produce 1
μmol of fatty acid (as palmitic acid) per minute. The enzyme was adsorbed completely on Accurel EP 100 (particle size <200
μm) with 20.5% activity retained. The soluble and the immobilized lipase OF showed optimal activity at the same pH and temperature
(pH 6.5–7.5 and 35°C). However, the immobilized lipase had a wider range of pH and higher temperature stability. Continuous
hydrolysis of palm olein was performed in a packed-bed reactor with 656 U of immobilized enzyme. The substrate (20% palm olein
in isooctane) and Tris/maleate buffer were fed concurrently at the flow rates of 0.08 and 0.04 mL/min, respectively. The system
gave a degree of hydrolysis (DH) of 90–100% for up to 250 h. A more stable system allowing for more than 300 h operation at
DH>95% was achieved by mixing the immobilized enzyme with 1000–1500 μm Accurel EP100 to increase the system porosity and continuous
feeding of the aqueous phase recycling from the product mixture. A similar result was also obtained using 1007 U of the immobilized
enzyme and 60% palm olein in isooctane fed at 0.06 mL/min. 相似文献
10.
Hydrolysis of olive oil, soybean oil, mink fat, lard, palm oil, coconut oil, and a hydrogenated, hardened oil with lipase
from anAspergillus sp. has been studied. The lipase had high specific activity (60,000 U/g) and did not show any positional specificity. The
lipase proved to be a more effective catalyst than Lipolase fromA. oryzae, with an optimal activity at 37°C and pH 6.5–7.0. It was activated by Ca2+ but inactivated by organic solvents such as isopropanol and propanone. All substrates examined could be hydrolyzed to corresponding
fatty acids with this enzyme at concentrations of 5–30 U/meq with yields of 90–99% in 2–24 h. The degree of hydrolysis was
almost logarithmically linear with reaction time and occurred in two stages. The lipase was stable and could be repeatedly
recycled for hydrolysis. 相似文献
11.
Y. -Y. Linko M. Lämsä A. Huhtala P. Linko 《Journal of the American Oil Chemists' Society》1994,71(12):1411-1414
Lipase-catalyzed transesterification (alcoholysis) of lowerucic acid rapeseed oil and 2-ethyl-1-hexanol without an additional
organic solvent was studied in stirred batch reactors. Of a number of commercially available enzymes investigated, the best
results were obtained with aCandida rugosa lipase. The optimal transesterification conditions were an oil/alcohol molar ratio of 1∶2.8, a minimum of 1.0% (w/w) added
water, and with a temperature of 37–55°C. Under the optimal conditions, a nearly complete conversion was obtained in one hour
with 14.6% (w/w) lipase, whereas 0.3% (w/w) lipase required 10 h for similar results. The enzyme was inactivated at 60°C. 相似文献
12.
Delphine Briand Eric Dubreucq Pierre Galzy 《Journal of the American Oil Chemists' Society》1995,72(11):1367-1373
This study describes the influence of various factors on the hydrolysis and alcoholysis activities of the lipase fromCandida parapsilosis (Ashford), Langeron and Talice in aqueous media. Optimal activities were obtained at 45°C and pH 6–6.5. The influence of
the nature of the substrate on the temperature activity profiles was observed. Total or partial recovery of the activities
was obtained when methanol was added to the enzyme extract after thermal denaturation. A tyrosin residue appeared to be necessary
for lipase function. Magnesium was a required metal cofactor. These activities were optimal in the presence of high amounts
of water (water activity >0.9). 相似文献
13.
Lipase B (GCB) produced by the fungus Geotrichum candidum CMICC 335426 is known for its high specificity towards cis-Δ9 unsaturated fatty acids. The wild-type lipase (not genetically modified) as well as the lipase obtained by heterologous
expression of the corresponding gene in Pichia pastoris (genetically modified) were studied in a process aiming to produce an oil containing very little saturated fatty acids (SAFA).
The approach described in this paper is based on the selective hydrolysis of sunflower oil (12% SAFA) using the G. candidum type B (GCB) lipases. Depending on the lipase input, up to 60% w/w degree of hydrolysis was obtained within 6–8 h. Because
of the high specificity of the GCB lipases (specificity factor ∼30), the level of unsaturates in the free fatty acid fraction
was >99% w/w. In contrast with literature data, no loss of specificity was observed, even at the highest degree of hydrolysis
obtained. Though both GCB lipases are stable at 30°C, the rate of hydrolysis decreased considerably during the process. Product
inhibition as well as time-dependent deactivation (half-life ≈2 h) were shown to be involved. After separation of the oil
phase, the unsaturated free fatty acids were recovered from the mixture by evaporation and reconverted to triglycerides by
enzymatic esterification with glycerol. Because the GCB lipases have a very low efficiency for esterification, this reaction
was carried out with immobilized Rhizomucor miehei lipase. Under continuous removal of the water generated during the process, >95% triglycerides were obtained in less than
24 h. Standard deodorization resulted in an odorless, colorless, and tasteless oil with less than 1% SAFA. 相似文献
14.
Yuji Shimada Akio Sugihara Hirofumi Nakano Tomomi Yokota Toshihiro Nagao Sadao Komemushi Yoshio Tominaga 《Journal of the American Oil Chemists' Society》1996,73(11):1415-1420
An attempt was made to produce structured lipids containing essential fatty acid by acidolysis with 1,3-positional specificRhizopus delemar lipase. The lipase was immobilized on a ceramic carrier by coprecipitation with acetone and then was activated by shaking
for 2 d at 30°C in a mixture of 5 g safflower or linseed oil, 10 g caprylic acid, 0.3 g water and 0.6 g of the immobilized
enzyme. The activated enzyme was transferred into the same amount of oil/caprylic acid mixture without water, and the mixture
was shaken under the same conditions as for the activation. By this reaction, 45–50 mol% of the fatty acids in oils were exchanged
for caprylic acid, and the immobilized enzyme could be reused 45 and 55 times for safflower and linseed oils, respectively,
without any significant loss of activity. The triglycerides were extracted withn-hexane after the acidolysis and then were allowed to react again with caprylic acid under the same conditions as mentioned
above. When acidolysis was repeated three times with safflower oil as a starting material, the only products obtained were
1,3-capryloyl-2-linoleoylglycerol and 1,3-capryloyl-2-oleoyl-glycerol, with a ratio of 86∶14 (w/w). Equally, the products
from linseed oil were 1,3-capryloyl-2-α-linolenoyl-glycerol, 1,3-caprylol-2-linoleoyl-glycerol, and 1,3-capryloyl-2-oleoly-glycerol
(60∶22∶18, w/w/w). All fatty acids at the 1,3-positions in the original oils were exchanged for caprylic acid by the repeated
acidolyses, and the positional specificity ofRhizopus lipase was also confirmed to be strict. 相似文献
15.
S. Hari Krishna B. Manohar S. Divakar N. G. Karanth 《Journal of the American Oil Chemists' Society》1999,76(12):1483-1488
Immobilized lipase from Mucor miehei (Lipozyme IM-20) was employed in the esterification of butyric acid and isoamyl alcohol to synthesize isoamyl butyrate in
n-hexane. Response surface methodology based on five-level, five-variable central composite rotatable design was used to evaluate
the effects of important variables—enzyme/substrate (E/S) ratio (5–25 g/mol), acid concentration (0.2–1.0 M), alcohol concentration
(0.25–1.25 M), incubation period (12–60 h), and temperature (30–50°C)—on esterification yield of isoamyl butyrate. In the
range of parameters studied, the extent of esterification decreased with temperature, lower E/S ratios, and incubation periods.
Excess acid and alcohol concentrations (i.e., acid/alcohol >1.4 or alcohol/acid >1.4) were found to decrease yield probably
owing to inhibition of the enzyme by acid or alcohol, the former being more severe. The optimal conditions achieved are as
follows: E/S ratio, 17 g/mol; acid concentration, 1.0 M; incubation period, 60 h; alcohol concentration, 1.25 M; and temperature,
30°C. With these conditions, the predicted value was 1.0 M ester, and the actual experimental value was 0.98 M. 相似文献
16.
Hubert Maehr Gladys Zenchoff David L. Coffen 《Journal of the American Oil Chemists' Society》1994,71(5):463-467
Commercially available fish oils with n−3 fatty acid contents ranging from 29 to 34% were converted enzymically, with Amano
P lipase, to mixtures of glycerides with n−3 fatty acid contents ofca. 50%, in weight recovery yields of 23–50%, depending upon extraction procedures. Glyceride mixtures with n−3 fatty acid contents
above 70% were obtained in yields of 14–21%. The processes are based on the relative stability of the ester linkages that
involve n−3-fatty acyl groups and the regioselectivity of the enzyme toward acyl groups at the 1,3-positions of glycerol.
This paper was presented at the 82nd AOCS Annual Meeting, May 12–15, 1991. 相似文献
17.
S. Bourg-Garros N. Razafindramboa A. A. Pavia 《Journal of the American Oil Chemists' Society》1997,74(11):1471-1475
(Z)-3-Hexen-1-yl butyrate is an important flavor and fragrance compound as it represents the model of a natural herbaceous (green)
note. Two immobilized lipases from Mucor miehei (Lipozym IM) and from Candida antarctica (Novozym 435) were investigated for their use in the synthesis of (Z)-3-hexen-1-yl butyrate by direct esterification in n-hexane. To determine optimal conditions for esterification, we examined the following parameters: temperature, amount of
lipase, acid/alcohol ratio, and absence of solvent. In n-hexane, bioconversion yields reached 95 (after 4 h) and 92% (after 6 h) for, respectively, Lipozym IM [17 (w/w reactants)]
and Novozym 435 [2% (w/w reactants)]. In the absence of solvent, at 60°C, Novozym 435-catalyzed esterification afforded the
title compound in 80% yield. Up to 250 g (in hexane) and 160 g (without solvent) of ester were easily prepared, in a single
operation, at a laboratory scale, in few hours, using 2% (w/w reactants) lipase. 相似文献
18.
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
19.
Taeko Izumi Yoshihiro Yagimuma Masanori Haga 《Journal of the American Oil Chemists' Society》1997,74(7):875-878
Enyzmatic amidation of the primary amines β-alanine ethyl ester and 3-aminopropionitrile with methyl laurate by means of immobilized
lipase (Candida antarctica lipase, CAL) resulted in the formation in good yield of N-lauroyl-β-alanine ethyl ester and 3-(N-lauroylamino)-propionitrile, respectively. When 3-amino-propionitrile was used as substrate, diisopropyl ether was a suitable
solvent. Changing the reaction temperature (12–80°C) did not affect the yields, and room temperature was a suitable temperature
for this reaction. In the investigation of reaction conditions, the use of equimolar amounts (5 mmol) of substrate and ester,
along with 0.5 g of CAL, in diisopropyl ether gave the best yield (99.3%) after 24 h of incubation at 24°C. The enzyme activity
in the amidation reaction did not decrease even after six uses. With β-alanine ethyl ester hydrochloride as substrate, diisopropyl
ether was unsuited as a solvent owing to the low solubility of the substrate in this solvent.
In this reaction, the best yield (82.0%) was attained by using dioxane as solvent. CAL achieved higher extents of amide synthesis
with long-chain than with short-chain ester substrates. The enzyme accepted only nonbulky primary amines as substrates. 相似文献
20.
Gao Sujun Zhang Daijia Sun Yaqin Xiu Zhilong 《Frontiers of Chemical Engineering in China》2007,1(2):202-207
The separation of 1,3-propanediol from the glycerol-based fermentation broth of Klebsiella pneumoniae plays an important role during the microbial production of 1,3-propanediol. In this paper, the separation of 1,3-propanediol
from fermentative broth by a combination of ultrafiltration and alcohol dilution crystallization was investigated. The broth
was first filtered by ultrafiltration, and 99% of cells, 89.4% of proteins and 69% of nucleic acids were removed. The obtained
broth was further condensed by vacuum distillation, and then alcohol was added. The macromolecular impurities, such as nucleic
acids, polysaccharides and proteins, were precipitated, and inorganic and organic salts were crystallized. The optimal volume
ratio of alcohol added to the condensed fermentation broth was determined to be 2:1. As a result, proteins, nucleic acids
and electric conductivity decreased by 97.4%, 89.7% and 95.8%, respectively, compared with the fermentative broth. The influences
of pH and water content in condensed broth on alcohol precipitation and dilution crystallization were also investigated. The
experimental results indicated that alcohol precipitation and dilution crystallization was feasible and effective for the
separation of 1,3-propanediol from actual fermentation broth.
Translated from The Chinese Journal of Process Engineering, 2006, 6(3): 454–457 [译自: 过程工程学报] 相似文献