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1.
Enzymatic esterification of starch using recovered coconut oil 总被引:3,自引:0,他引:3
Rajan A Prasad VS Abraham TE 《International journal of biological macromolecules》2006,39(4-5):265-272
Modification of maize and cassava starches was done using recovered coconut oil and microbial lipase. Microwave esterification was advantageous as it gave a DS 1.55 and 1.1 for maize starch and cassava starch, respectively. Solution state esterification of cassava starch for 36 h at 60 °C gave a DS of 0.08 and semi-solid state esterification gave a DS of 0.43. TGA and DSC studies showed that the higher DS attributed to the thermostability, since onset of decomposition is at a higher temperature (492 °C) than the unmodified (330 °C) and was stable above 600 °C. -Amylase digestibility and viscosity reduced for modified starch. 相似文献
2.
Mohd. Basyaruddin Abdul Rahman Noor Mona Md Yunus Mohd Zobir Hussein Raja Noor Zaliha Raja Abdul Rahman Abu Bakar Salleh Mahiran Basri 《Biocatalysis and Biotransformation》2013,31(3-4):233-239
Ni/Al-layered double hydroxides (Ni-LDHs) and Ni/Al-sodium dodecyl sulfonate layered double hydroxide nanocomposites (Ni-SDS-LDHs) with a molar ratio of Ni:Al (4:1) have been prepared by a co-precipitation (or salt-base) method. Their structures were determined using Powder X-Ray Diffractometer (PXRD) and the spectra showed that basal spacings for Ni-LDHs and Ni-SDS-LDHs synthesised were around 8.1?Å and 34.8?Å, respectively. Lipase from Candida rugosa was immobilised onto these advanced materials, by physical adsorption. The activity of immobilised lipase was investigated through esterification of palmitic acid and isopropyl alcohol in hexane. The effects of reaction temperature, thermostability, stability in organic solvent, operational stability, leaching and storage studies of the immobilised lipase were investigated. These biocatalysts exhibited higher activities than the native lipase with an optimum temperature of 40°C. Immobilised lipases showed higher storage stability than native lipase (up to 60 days) and during operational studies at 30°C for 5?h, more than 50% of its activity was retained. Leaching studies showed that physical adsorption is suitable for the attachment of enzymes onto LDHs. 相似文献
3.
Hong-de Yan Zhao Wang Ling-jie Chen 《Journal of industrial microbiology & biotechnology》2009,36(5):643-648
Kinetic resolution of α-lipoic acid, a case of remote stereocenter discrimination, was accomplished using lipase from Aspergillus oryzae WZ007. Performance of this lipase was investigated for enantioselective esterification of (S)-α-lipoic acid, leaving the target product (R)-α-lipoic acid in unreacted form. The effects of chain length of alcohol, type of solvent, molar ratio of alcohol:acid, and
reaction temperature were studied. The optimum reaction conditions were found to be esterification with n-octanol at 50°C in heptane with an alcohol:acid molar ratio of 5:1. The conversion rate of α-lipoic acid was 75.2%, with
an enantiomeric excess of 92.5% towards unreacted substrate in a reaction time of 48 h. 相似文献
4.
Summary A lipase from Candida rugosa immobilized on styrene-divinylbenzene copolymer was used to catalyse the direct esterification of butanol and butyric acid. A factorial design was employed to evaluate the effects of temperature (37–50 °C), substrate molar ratio of butyric acid to butanol (0.6 to 2.0) and enzyme amount (0.2–0.4 g) on the ester yield. The main effects were fitted by multiple regression analysis to a linear model and maximum ester yield could be obtained working at 41 °C with 0.4 g of lipase. The mathematical model obtained, representing the ester yield has been found to describe adequately the experimental results. Under optimal conditions, concentration of 32.4 g butyl butyrate/l that corresponds to a yield of 75% was obtained. 相似文献
5.
O-Pentynyl dextran (PyD), an amphiphilic polysaccharide derivative with a degree of substitution (DS) of 0.43 was compared
with ion exchange resins Lewatit VP OC 1600, Amberlite XAD 761 and Duolite A568 for immobilization of Lipase from Rhizopus arrhizus by adsorption method. The immobilized enzymes were employed for esterification of octanoic acid with geraniol in n-hexane as model reaction. PyD showed higher lipase adsorption and with 249 μmol min−1 g−1 significant higher esterification activity than the other supports (67–83 μmol min−1 g−1). Biocatalysts from all types of supports except PyD became completely inactive within 8 weeks storing at −10 °C while lipase
immobilized on PyD retained its full esterification activity for at least 14 weeks. In repeated use, yield decreased rapidly
after two cycles for all supports except for PyD. For this biopolymeric support, constantly 90% yield was achieved even after
eight cycles, when the biocatalyst was washed with n-hexane and water and then freeze-dried. To achieve this yield, prolonged reaction times were required, partly on the account
of an increasing delay period, probably to adapt active conformation, until the reaction starts. 相似文献
6.
S. Suresh Kumar Lalit Kumar Vikram Sahai Rani Gupta 《Journal of industrial microbiology & biotechnology》2009,36(3):427-432
An alkaline lipase from Trichosporon asahii MSR 54 was used to develop presoak formulation for removing oil stains at ambient temperature. The lipase was produced in
a reactor followed by concentration by ultrafiltration and then it was dried with starch. The biochemical characteristics
of enzyme showed that it was an alkaline lipase having pH activity in the range of pH 8.0–10.0 and temperature in the range
of 25–50°C. The present lipase was active >80% at 25°C. The lipase was cystein activated with fourfold enhancement in presence
of 5 mM cystein and likewise the activity was also stimulated in presence of papain hydrolysate which served as source of
cystein. The presoak formulation consisted of two components A and B, component A was enzyme additive and B was a mixture
of carbonate/bicarbonate source of alkali and papain hydrolysate as source of cystein. The results indicated that the presoaking
in enzyme formulation followed by detergent washing was a better strategy for stain removal than direct washing with detergent
in presence of lipase. Further, it was observed that 0.25% presoak component B in presence of 100 U enzyme component A (0.1 g)
was the best formulation in removing maximum stain from mustard oil/triolein soiled clothes as indicated by increase in reflectance
which was found equal to that of control cloth. The lipase action in presoaked formulation was clearly indicated by quantitated
fatty acid release and also the TLC results of wash water, where oil hydrolytic products were visible only in presence of
enzyme in the treatment. The wash performance carried at 25°C indicated that washing at 25°C was at par with that at 40°C
as indicated by similar reflectance of the washed cloth piece though qualitative fatty acid release was higher at 40°C. 相似文献
7.
The esterification reaction between stearic acid and lactic acid using Rhizomucor miehei lipase and porcine pancreas lipase was optimized for maximum esterification using response surface methodology. The formation
of the ester was found to depend on three parameters namely enzyme/substrate ratio, lactic acid (stearic acid) concentration
and incubation period. The maximum esterification predicted by theoretical equations for both lipases matched well with the
observed experimental values. In the case of R. miehei lipase, stearoyl lactic acid ester formation was found to increase with incubation period and lactic acid (stearic acid)
concentrations with maximum esterification of 26.9% at an enzyme/substrate (E/S) ratio of 125 g mol−1. In the case of porcine pancreas lipase, esterification showed a steady increase with increase in incubation period and lactic
acid (stearic acid) concentration independent of the E/S ratios employed. In the case of PPL, a maximum esterification of
18.9% was observed at an E/S ratio of 25 g mol−1 at a lactic acid (stearic acid) concentration of 0.09 M after an incubation period of 72 h.
Received: 12 February 1999 / Received revision: 31 May 1999 / Accepted: 4 June 1999 相似文献
8.
Shamsher Singh Kanwar Hemant Kumar Verma Rajeev Kumar Kaushal Reena Gupta Swapandeep Singh Chimni Yogesh Kumar Ghansham Singh Chauhan 《World journal of microbiology & biotechnology》2005,21(6-7):1037-1044
Summary A purified alkaline thermo-tolerant bacterial lipase from Pseudomonas aeruginosa BTS-2 was immobilized on a poly (AAc-co-HPMA-cl-MBAm) hydrogel network. The hydrogel showed approximately 95% binding efficiency for lipase (specific activity 1.96 U mg−1). The immobilized enzyme achieved 65.1% conversion of ethanol and propionic acid (100 mM each) into ethyl propionate in n-nonane at 65 °C in 9 h. When alkane of C-chain length lower than n-nonane was used as the organic solvent, the conversion of ethanol and propionic acid into ethyl propionate decreased with
a decrease in the log P value of alkanes. The immobilized lipase retained approximately 30% of its original catalytic activity after five cycles
of reuse for esterification of ethanol and propionic acid into ethyl propionate at temperature 65 °C in 3 h. Addition of a
molecular sieve (3 ?) to the reaction mixture enhanced the formation of ethyl propionate to 89.3%. Moreover, ethanol and propionic
acid when taken a molar ratio of 3:1 further promoted the conversion rate to 94%. However, an increase in the molar ratio
of propionic acid with respect to ethanol resulted in a decline of ethyl propionate synthesis. 相似文献
9.
《Journal of Molecular Catalysis .B, Enzymatic》2011,69(3-4):230-239
The Talaromyces thermophilus lipase (TTL) was immobilized by different methods namely adsorption, ionic binding and covalent coupling, using various carriers. Chitosan, pre-treated with glutaraldehyde, was selected as the most suitable support material preserving the catalytic activity almost intact and offering maximum immobilization capacity (76% and 91%, respectively). The chitosan-immobilized lipase could be reputably used for ten cycles with more than 80% of its initial hydrolytic activity. Shift in the optimal temperature from 50 to 60 °C and in the pH from 9.5 to 10, were observed for the immobilized lipase when compared to the free enzyme.The catalytic esterification of oleic acid with 1-butanol has been carried out using hexane as organic solvent. A high performance synthesis of 1-butyl oleate was obtained (95% of conversion yield) at 60 °C with a molar ratio of 1:1 oleic acid to butanol and using 100 U (0.2 g) of immobilized lipase. The esterification product is analysed by GC/MS to confirm the conversion percentage calculated by titration. 相似文献
10.
Young‐Gil Pyo Seung In Hong Yangha Kim Byung Hee Kim In‐Hwan Kim 《Biotechnology progress》2012,28(5):1218-1224
High purity monoacylglycerol (MAG) containing pinolenic acid was synthesized via stepwise esterification of glycerol and fatty acids from pine nut oil using a cold active lipase from Penicillium camembertii as a biocatalyst. Effects of temperature, molar ratio, water content, enzyme loading, and vacuum on the synthesis of MAG by lipase‐catalyzed esterification of glycerol and fatty acid from pine nut oil were investigated. Diacylglycerol (DAG) as well as MAG increased significantly when temperature was increased from 20 to 40°C. At a molar ratio of 1:1, MAG content decreased because of the significant increase in DAG content. Water has a profound influence on both MAG and DAG content through the entire course of reaction. The reaction rate increased significantly as enzyme loading increased up to 600 units. Vacuum was an effective method to reduce DAG content. The optimum temperature, molar ratio, water content, enzyme loading, vacuum, and reaction time were 20°C, 1:5 (fatty acid to glycerol), 2%, 600 units, 5 torr, and 24 h, respectively. MAG content further increased via lipase‐catalyzed second step esterification at subzero temperature. P. camembertii lipase exhibited esterification activity up to ?30°C. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012 相似文献
11.
Commercial lipase preparations and mycelium bound lipase from Aspergillus niger NCIM 1207 were used for esterification of acetic acid with isoamyl alcohol to obtain isoamyl acetate. The esterification
reaction was carried out at 30°C in n-hexane with shaking at 120 rpm. Initial reaction rates, conversion efficiency and isoamyl acetate concentration obtained
using Novozyme 435 were the highest. Mycelium bound lipase of A. niger NCIM 1207 produced maximal isoamyl acetate formation at an alcohol/acid ratio of 1.6. Acetic acid at higher concentrations
than required for the critical alcohol/acid ratio lower than 1.3 and higher than 1.6 resulted in decreased yields of isoamyl
acetate probably owing to lowering of micro-aqueous environmental pH around the enzyme leading to inhibition of enzyme activity.
Mycelium bound A. niger lipase produced 80 g/l of isoamyl acetate within 96 h even though extremely less amount of enzyme activity was used for esterification.
The presence of sodium sulphate during esterification reaction at higher substrate concentration resulted in increased conversion
efficiency when we used mycelium bound enzyme preparations of A. niger NCIM 1207. This could be due to removal of excess water released during esterification reaction by sodium sulphate. High
ester concentration (286.5 g/l) and conversion (73.5%) were obtained within 24 h using Novozyme 435 under these conditions. 相似文献
12.
Long-chain acyl thioesters (thio wax esters) have been prepared in high (80% to more than 90%) yields by solvent-free esterification
of fatty acids (lauric, myristic, palmitic and stearic acids) with long-chain thiols, such as decane thiol, dodecane thiol,
tetradecane thiol and hexadecane thiol, catalysed by lipases from Candida antarctica (Novozym) and Rhizomucor miehei (Lipozyme) in the presence of a 0.4-nm molecular sieve. In the thioesterification reaction Novozym was a more effective biocatalyst
than Lipozyme. The extent of thioesterification increased with increasing molar ratio of fatty acid to alkane thiol (1:1 to
3:1) and with temperature (40 °C compared to 60 °C), as well as with the amount of the enzyme preparation and the amount of
0.4-nm molecular sieve. Decreasing the chain length of the alkane thiol from C16 to C10 also increased the extent of thioesterification. Lipase-catalysed solvent-free transthioesterification of fatty acid methyl
esters with alkane thiols was less effective for the preparation of acyl thioesters than was thioesterification of fatty acids
with alkane thiols. In transthioesterification, Lipozyme was slightly more effective as a biocatalyst than Novozym.
Received: 3 September 1998 / Received revision: 18 November 1998 / Accepted: 21 November 1998 相似文献
13.
Influence of Cross-linked Waxy Maize Starch on the Aggregation Behavior of Casein Micelles During Acid-induced Gelation 总被引:1,自引:0,他引:1
The influence of cross-linked waxy maize starch on the aggregation behavior of casein micelles was investigated using a combination
of physico-chemical techniques. Milk was homogenized at two different temperatures (55 and 65 °C) and then heated at 95 °C
for 5 min in a pilot scale system. The possible interactions between modified starch and milk proteins during lactic acid
fermentation were evaluated. While 1% starch did not show differences in the whey protein complexes formed during heating
compared to milk with no starch (as measured by size exclusion chromatography), a higher (2.5%) concentration of starch clearly
showed an increased amount of heat-induced whey protein aggregates. The gelation pH also increased significantly with 2.5%
starch compared to that of the control samples. The storage modulus (G′) increased with increasing levels of starch, and confocal
microscopy confirmed that the microstructure of the casein gels was altered by the presence of modified starch. Milk-starch
mixtures preheated and homogenized at 55 or 65 °C exhibited similar physico-chemical behavior during acidification. The results
suggested a lack of interaction between starch granules and casein micelles during acidification, and scanning electron microscopy
images collected with a self-assembled monolayer technique also confirmed that starch granules were not attached to milk caseins
but only embedded in the protein gel matrix. 相似文献
14.
Isooctane was the best reaction medium for the enantioselective esterification of (R,S)-2-methylalkanoic acid with n-butanol using Carica papaya lipase as catalyst. Increasing linear alkyl-chain length of racemic 2-methylalkanoic acids from ethyl to hexyl increased
the enantioselectivity (E) from 2.1 to 98.2 for the esterification of racemic 2-methylalkanoic acids with n-butanol at 35°C. Decreasing reaction temperature from 40 to 20°C increased the enantioselectivity (E) from 14 to 33 for the esterification of racemic 2-methylhexanoic acids with n-butanol. We obtained a maximum enantioselectivity, of E = 24.3, for the enantioselective esterification of racemic 2-methylhexanoic acids with n-butanol in isooctane at water activity 0.33, and at 35°C. 相似文献
15.
Lipase catalyzed production of monoacylglycerols by the esterification of fish oil fatty acids with glycerol 总被引:1,自引:0,他引:1
Hee-Guk Byun Tae-Kil Eom Won-Kyo Jung Se-Kwon Kim 《Biotechnology and Bioprocess Engineering》2007,12(5):491-496
In this study, we attempted the efficient production of monoacylglycerols (MAG) via the lipase-catalyzed esterification of
glycerol with fatty acids obtained from sardine oil. The reaction factors that influenced MAG synthesis were the glycerol
to fatty acid mole ratio, amount of enzyme, organic solvent, temperature, and the type of lipase used. Porcine pancreas lipase
was selected to catalyze this reaction. The optimum conditions we determined for MAG synthesis were a glycerol to fatty acid
mole ratio of 1∶6, 100 mg/mL of lipase, and 30°C in dioxane. Under these conditions, the MAG content was 68% (w/w) after 72
h of reaction. The MAGs synthesized via the lipase-catalyzed esterification of glycerol with fatty acids included monomyristin,
monopamiltin, and monoolein, as identified by GCMS. 相似文献
16.
Dasciana S. Rodrigues George P. Cavalcante Giovanilton F. Silva Andrea L. O. Ferreira Luciana R. B. Gonçalves 《World journal of microbiology & biotechnology》2008,24(6):833-839
In this work, the stabilizing effect of bovine serum albumin (BSA), peptone (PEP), and polyethylene glycol (PEG) during immobilization
of Candida antarctica lipase on activated carbon was investigated. The influence of enzyme concentration and type of additive, added during the
immobilization procedure, was studied using a 22 factorial central composite design. The goal was to maximize the synthetic activity of butyl butyrate, using butyric acid
and butanol as substrate in n-heptane. An increase of 31–58% in the esterification activity was obtained when enzyme concentration on the supernatant was
enhanced from 86.50 U m L−1 to 226.80 U mL−1. An enhancement in esterification activity of 38–68.95% was observed, depending on the initial enzyme concentration, when
PEP was used instead of BSA. No significant increase in the esterification activity was observed when PEP was replaced by
PEG. However, thermal stability tests at 50 °C showed that PEG had a higher stabilizing effect. 相似文献
17.
Vania Castriani Fernandes da Silva Fabiano Jares Contesini Patrícia de Oliveira Carvalho 《Journal of industrial microbiology & biotechnology》2009,36(7):949-954
Considering the extraordinary microbial diversity and importance of fungi as enzyme producers, the search for new biocatalysts
with special characteristics and possible applications in biocatalysis is of great interest. Here, we report the performance
in the resolution of racemic ibuprofen of a native enantioselective lipase from Aspergillus niger, free and immobilized in five types of support (Accurel EP-100, Amberlite MB-1, Celite, Montmorillonite K10 and Silica gel).
Amberlite MB-1 was found to be the best support, with a conversion of 38.2%, enantiomeric excess of 50.7% and enantiomeric
ratio (E value) of 19 in 72 h of reaction. After a thorough optimization of several parameters, the E value of the immobilized Aspergillus niger lipase was increased (E = 23) in a shorter reaction period (48 h) at 35°C. Moreover, the immobilized Aspergillus niger lipase maintained an esterification activity of at least 80% after 8 months of storage at 4°C and could be reused at least
six times. 相似文献
18.
Takashi Kobayashi Taro Ehara Takanori Mizuoka Shuji Adachi 《Biotechnology letters》2010,32(11):1679-1684
In order to synthesize a sugar ester at high concentration, 1,2-O-isopropylidene-α-d-glucofuranose (IpGlc), which is one of the sugar acetals and is more hydrophobic than unmodified glucose, was esterified
with palmitic acid at 40°C using immobilized lipase from Candida antarctica in some organic solvents or their mixtures. Acetone + t-butyl alcohol (3:1 v/v) improved both the initial reaction rate and yield after 80 h: the product reached its maximum value
(240 mmol/kg solvent; ca. 110 g/kg solvent) when 400 mmol IpGlc/kg solvent and 1,200 mmol palmitic acid/kg solvent were used
in this solvent mixture. 相似文献
19.
Thermomyces lanuginosus lipase (Lipozyme TLIM)-catalyzed esterification of l-ascorbic acid was studied. It was suggested that Lipozyme TLIM was a suitable biocatalyst for enzymatic esterification of
l-ascorbic acid. Three solvents were investigated for the reaction, and acetone was found to be a suitable reaction medium.
Furthermore, it was found that water activity could notably affect the conversion. Moreover, pH memory of Lipozyme TLIM lipase
for catalyzing l-ascorbic acid esterification in acetone was observed and the effect of pH on the reaction was estimated. In addition, the
influences of other parameters such as substrate mole ratio, enzyme loading, and reaction temperature and reusability of lipase
on esterification of l-ascorbic acid were also analyzed systematically and quantitatively. Kinetic characterization of Lipozyme TLIM showed that
K
m,a and V
max were 80.085 mM and 0.747 mM min−1, respectively. As a result, Lipozyme TLIM-catalyzed esterification of l-ascorbic acid gave a maximum conversion of 99%. 相似文献
20.
A total of 338 aerobic heterotrophic bacterial strains were isolated from Arctic sea ice, Canada Basin (77°30′N–80°12′N).
The capability of the isolates to produce protease, lipase, amylase, chitinase, β-galactosidase, cellulase and/or agarase
was investigated. Isolates that were able to degrade tributyrin, skim milk, starch, lactose and chitin accounted for 71.6,
65.7, 38.5, 31.6 and 16.9% of sea ice strains, respectively. Lipase producers and/or protease producers were phylogenetically
widespread among the isolated strains. Starch and/or lactose hydrolytic strains were mainly distributed among Colwellia, Marinomonas, Pseudoalteromonas, Pseudomonas and Shewanella isolates. Pseudoalteromonas tetraodonis, Pseudoalteromonas
elyakovii, Bacillus firmus and Janibacter melonis isolates all have the ability to degrade chitin. Only some strains belonging to Pseudoalteromonas genus scored positive for agarase (6) and cellulose (9). The temperature dependences for lipase activities were determined
for five psychrophilic and six psychrotolerant bacteria. At low temperatures, the psychrophilic bacterial lipase activity
was not significantly higher than psychrotolerant bacterial lipase, though all lipases showed remarkably high activity with
10–36% residual activity at 0°C. 相似文献