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purification of conjugated linoleic acid isomers through a process including lipase-catalyzed selective esterification.a mixture of conjugated linoleic acids (clas) was prepared by alkali conjugation of high purity linoleic acid. the preparation contained 45.1 wt% cis-9, trans-11 (c9,t11)-cla, 46.8 wt% trans-10, cis-12 (t10,c12)-cla, and 5.3 wt% other clas. a process comprising candida rugosa lipase-catalyzed selective esterification with lauryl alcohol, molecular distillation, and urea adduct fractionation under strict conditions in ethanol was very effective for purification of c9,t11- and t10,c12-clas. in par ...200312843679
immobilization of lipases and assay in continuous fixed bed reactor.lipases are versatile enzymes regarding the range of reactions they catalyse and substrates on which they act. they are as well important as catalyst in organic synthesis. their immobilization on appropriate supports confer them greater stability besides the possibility of operating in continuous reactors. in order to explore these abilities, the reactions involving hydrolysis of p-nitrophenyl acetate (pnpa) and transesterification of pnpa with n-butanol were chosen. lipases from two different s ...200314683514
effects of preparative parameters on the properties of chitosan hydrogel beads containing candida rugosa lipase.the influences of the ph, tripolyphosphate (tpp) concentration, and ionic strength of the gelling medium on the entrapment efficiency, release, and activity of lipase in chitosan hydrogel beads were studied. a solution of candida rugosa lipase was prepared in a 1.5% w/v chitosan and 1% (v/v) acetic acid medium, and dropped into a tpp solution. release of lipase in ph 7.2 tris buffer was monitored over 36 h using the micro bca protein assay. the activity of the entrapped enzyme was assayed using ...200414751751
high-yield conversion of (r)-2-octanol from the corresponding racemate by stereoinversion using candida rugosa.whole cells of candida rugosa catalyzed the conversion of (r)-2-octanol from the corresponding racemate with the optical purity of 97% e.e. and yield of 92% in 10 h. the product was formed through a stereoinversion involving enantioselective oxidation and asymmetric reduction with 2-octanone as the intermediate.200515685415
characteristics of immobilized lipase on hydrophobic superparamagnetic microspheres to catalyze esterification.a novel immobilized lipase (from candida rugosa) on hydrophobic and superparamagnetic microspheres was prepared and used as a biocatalyst to catalyze esterification reactions in diverse solvents and reaction systems. the results showed that the immobilized lipase had over 2-fold higher activities in higher log p value solvents. an exponential increase of lipase activity against log p of two miscible solvent mixtures was observed for the first time. both free and immobilized lipase achieved its m ...200415058995
activity of lipase in reversed micelles.the enzyme activity of lipase from candida rugosa in aot isooctane reversed micelles was investigated. effect of ph, temperature, substrate concentration, waterpool (r value), choice of organic solvent, surfactant concentration on the activity of lipase were studied in detail. results indicate that the enzyme in reversed micelles follows the michaelis-menten dynamics temperature optimum=32.5 degrees, ph optimum=7.0, and maximum activity is reached at the concentration of olive oil of 40%. the en ...199912115008
lipase-catalyzed acidolysis of menhaden oil with conjugated linoleic acid: effect of water content.the effect of the water content on the lipase-catalyzed (candida rugosa) interesterification (acidolysis) of menhaden oil with conjugated linoleic acid was studied for amounts of added water ranging from 0-4% (w/w). the rate of the acidolysis reaction increased with increasing water content, but the corresponding percentage of n-3 fatty acids liberated also increased. the implications of water content for minimization of the release of n-3 fatty acid residues while maximizing incorporation of cl ...200212115120
candida rugosa lipase-catalyzed intramolecular o- to n- transacylation of butyryl propranolol in the presence of cyclodextrins.in the present paper, a novel enzymatic reaction between (r,s)-o-butyryl propranolol (o-bp) and lipase from candida rugosa in the presence of hydroxypropyl-beta-cyclodextrin (hp-beta-cd) is described. under the used condition, lipase catalyzed the intramolecular transacylation of o-bp into n-butyryl propranolol (n-bp). propranolol, the product of the expected hydrolysis reaction, was not detected in the reaction medium. a chiral analysis of the reaction product indicated that lipase showed a pre ...200515801768
enzymatic resolution of (+/-)-5-acetoxy-4-aryl-(2e)-pentenoate derivatives.enzymatic resolution of six (+/-)-5-acetoxy-4-aryl-(2e)-pentenoate derivatives, compounds 9, 11, 13, 15, 17, and 19 bearing a different aromatic substitution pattern, using lipase of-360 from candida rugosa was carried out. the absolute configurations of all hydrolyzed products and all unchanged acetates were found to be s and r, respectively. moreover, the enantiomeric excess of the enzymatic resolution products from 9, 11, and 13 with the ortho-methoxyl group in the aromatic ring was higher th ...200515863931
wood cellulignin as an alternative matrix for enzyme immobilization.the objective of this work was to select an efficient methodology for preparing active samples of candida rugosa lipase immobilized in wood cellulignin, to be applied in hydrolysis and ester reactions. for this purpose, lipase was immobilized in the matrix by physical adsorption (pure cellulignin) and covalent binding (activated cellulignin with glutaraldeyde or carbonyldiimidazole [cdi]) in the presence or absence of polyethylene glycol (peg) (molecular mass of 1500 daltons) as stabilizing agen ...200515917604
characterisation of steryl esterase activities in commercial lipase preparations.triglycerides, steryl esters, resin acids, free fatty acids and sterols are lipophilic extractives of wood (commonly referred to as pitch or wood resin) and have a negative impact on paper machine runnability and quality of paper. thus, enzymes capable of modifying these compounds would be potential tools for reducing pitch problems during paper manufacture. in this work, 19 commercial lipase preparations were tested for their ability to degrade steryl esters, which may play a significant role i ...200414741769
continuous monitoring of cholesterol oleate hydrolysis by hormone-sensitive lipase and other cholesterol esterases.hormone-sensitive lipase (hsl) contributes importantly to the hydrolysis of cholesteryl ester in steroidogenic tissues, releasing the cholesterol required for adrenal steroidogenesis. hsl has broad substrate specificity, because it hydrolyzes triacylglycerols (tags), diacylglycerols, monoacylglycerols, and cholesteryl esters. in this study, we developed a specific cholesterol esterase assay using cholesterol oleate (co) dispersed in phosphatidylcholine and gum arabic by sonication. to continuous ...200515716583
hydrolytic resolution of (r,s)-naproxen 2,2,2-trifluoroethyl thioester by carica papaya lipase in water-saturated organic solvents.for the first time, the carica papaya lipase (cpl) stored in crude papain is explored as a potential enantioselective biocatalyst for obtaining chiral acids from their racemic thioesters. hydrolytic resolution of (r,s)-naproxen 2,2,2-trifluoroethyl thioester in water-saturated organic solvents is employed as a model system for studying the effects of temperature and solvents on lipase activity and enantioselectivity. an optimal temperature of 60 degrees c, based on the initial rate of (s)-thioes ...200515543625
activity and enantioselectivity of wildtype and lid mutated candida rugosa lipase isoform 1 in organic solvents.the activity and enantioselectivity of lipase 1 from candida rugosa and of a chimera enzyme obtained by replacing the lid of isoform 1 with the lid of isoform 3 were compared in organic solvents. the alcoholysis of chloro ethyl 2-hydroxy hexanoate with methanol and of vinyl acetate with 6-methyl-5-hepten-2-ol were used as model reactions in different reaction conditions. the chimera enzyme was less active and enantioselective than the wildtype in all the conditions tested. a rationale for such d ...200415052644
characterization of sol-gel bioencapsulates for ester hydrolysis and synthesis.candida rugosa lipase was entrapped in silica sol-gel particles prepared by hydrolysis of methyltrimethoxysilane and assayed by p-nitrophenyl palmitate hydrolysis, as a function of ph and temperature, giving ph optima of 7.8 (free enzyme) and 5.0-8.0 (immobilized enzyme). the optimum temperature for the immobilized enzyme (50-55 degrees c) was 19 degrees c higher than for the free enzyme. thermal, operational, and storage stability were determined with n-butanol and butyric acid, giving at 45 de ...200515930564
outbreak of candida rugosa mastitis in a dairy herd after intramammary antibiotic treatment. 200515965006
protein engineering and applications of candida rugosa lipase isoforms.commercial preparations of candida rugosa lipase (crl) are mixtures of lipase isoforms used for the hydrolysis and synthesis of various esters. the presence of variable isoforms and the amount of lipolytic protein in the crude lipase preparations lead to a lack of reproducibility of biocatalytic reactions. purification of crude crl improve their substrate specificity, enantioselectivity, stability, and specific activities. the expression of the isoforms is governed by culture or fermentation con ...200415554150
superparamagnetic nanoparticle-supported enzymatic resolution of racemic carboxylates.candida rugosa lipase immobilized on maghemite nanoparticles demonstrated high stereoselectivity in kinetic resolution of racemic carboxylates and improved long-term stability over its parent free enzyme, allowing the supported enzyme to be repeatedly used for a series of chiral resolution reactions.200516136241
studies on a novel carbon source and cosolvent for lipase production by candida rugosa.oleic acid esters were shown to be the best carbon source for both cell growth and lipase production by candida rugosa. use of a cosolvent, dodecane, in fermentations improved the solubility of solid substrates and increased oxygen solubility. this resulted in the highest lipase activity in batch fermentation with glycerol trioleate and dodecane. lipase activity reached 77.1 units ml(-1).200415069604
unambiguous detection of astaxanthin and astaxanthin fatty acid esters in krill (euphausia superba dana).hplc atmospheric pressure chemical ionization (apci)/ms, gc ms, hplc diode array detection (dad), and nmr were used for the identification of astaxanthin and astaxanthin fatty acid esters in krill (euphausia superba dana). matrix solid phase dispersion was applied for the extraction of the carotenoids. this gentle and expeditious extraction technique for solid and viscous samples leads to distinct higher enrichment rates than the conventional liquid-liquid extraction. the chromatographic separat ...200516224962
on-line determination of the total lipolytic activity in a four-phase system using a lipase adsorption law.lipases have a very well known affinity for organic-aqueous interfaces. a previously developed on-line turbidimetric analyser can only analyse the lipase activity present in the aqueous phase of a culture broth. an adsorption law of langmuir type has been derived to determine the lipolytic activity remaining in the organic-aqueous interface formed between oleic acid and culture broth in candida rugosa lipase production fermentation. in the concentration range of oleic acid (0-8 g.l(-1)) and lipo ...199916232505
preparation of detergent-lipase complexes utilizing water-soluble amphiphiles in single aqueous phase and catalysis of transesterifications in homogeneous organic solvents.a novel method of preparing detergent-enzyme complexes that can be employed in organic media was developed utilizing newly synthesized water-soluble nonionic gemini-type detergents, n,n-bis(3-d-gluconamidopropyl)-3-(dialkyl-l-glutamatecarbonyl)propanamides (big2cnca: n = 10,12,14,16,18) and n,n-bis(3-d-lactonamidopropyl)-3-(dialkyl-l-glutamatecarbonyl)propanamides (bil2cnca: n = 16,18), and nonionic twin-headed detergents, n,n-bis(3-d-gluconamidopropyl)alkanamides (big1cn: n = 12,14,16,18,delta9 ...200016232923
effect of methanol and water contents on production of biodiesel fuel from plant oil catalyzed by various lipases in a solvent-free system.methyl esters synthesized from plant oil and methanol by the methanolysis reaction are potentially important as a biodiesel fuel. the methanolysis of soybean oil by lipases from various microorganisms was investigated. several of the lipases were found to catalyze methanolysis in a water-containing system without an organic solvent. the lipases from candida rugosa, pseudomonas cepacia, and pseudomonas fluorescens displayed particularly high catalytic ability. the reaction rates of methanolysis c ...200116232938
modification of lipases with poly(ethylene glycol) and poly(oxyethylene) detergents and their catalytic activities in organic solvents.the alpha-chymotrypsin-poly(ethylene glycol) complex, which was prepared by lyophilizing an aqueous solution, was found to have high catalytic activity in organic media even when the molar ratio of polymer/enzyme in its preparation stage is unity. in this study, we obtained freeze-dried complexes of lipases and poly(ethylene glycol) or poly(oxyethylene) detergents including newly synthesized gemini-type detergents, and their transesterification activity in organic solvents was evaluated. the fre ...200116233142
enantioselective esterification of racemic ibuprofen in isooctane by immobilized lipase on cellulose acetate-titanium iso-propoxide gel fiber.lipase (candida rugosa) was entrap-immobilized on cellulose acetate-titanium iso-propoxide gel fiber by the sol-gel method. the immobilized lipase was used for the direct synthesis of (s)-ibuprofen ester from racemic ibuprofen using propyl alcohol as an acyl acceptor in isooctane. the activity of the immobilized lipase was decreased to about 10-20% that of native lipase. however, the reaction was more enantioselective compared to that with native lipase. the stability for repeated use was improv ...200216233173
enhanced enzyme activity and enantioselectivity of lipases in organic solvents by crown ethers and cyclodextrins.lipases from candida rugosa (crl) and pseudomonas cepacia (pcl) were co-lyophilized with cyclic oligoethers including four crown ethers and nine cyclodextrins (cyds), and their transesterification activity and enantioselectivity in organic solvents were evaluated. the pcl co-lyophilized with each additive showed simultaneously enhanced enzyme activity and enantioselectivity when compared to the native lipase lyophilized from buffer alone; in contrast, such enhancement was not observed for the co ...200316233437
effect of fermentation conditions in the enzymatic activity and stereoselectivity of crude lipase from candida rugosa.different fed-batch cultures of candida rugosa were carried out using oleic acid as the only carbon source. the crude lipases obtained under several operational conditions and downstream processes showed different catalytic activity and isoenzymes ratio. this fact implied that the performance of the lipase produced could be modulated by using different operational fermentation conditions. these powders were compared with commercial lipase from sigma (st. louis, mo) in hydrolysis and synthesis re ...199915304677
structure and dynamics of candida rugosa lipase: the role of organic solvent.the effect of organic solvent on the structure and dynamics of proteins was investigated by multiple molecular dynamics simulations (1 ns each) of candida rugosa lipase in water and in carbon tetrachloride. the choice of solvent had only a minor structural effect. for both solvents the open and the closed conformation of the lipase were near to their experimental x-ray structures (c(alpha) rms deviation 1-1.3 a). however, the solvents had a highly specific effect on the flexibility of solvent-ex ...200415597204
fabrication and application of enzyme-incorporated peptide nanotubes.enzyme engineering is a fast-growing field in the pharmaceutical and food markets. for those applications, various substrates have been examined to immobilize and stabilize enzymes. in this report, we examined peptide nanotubes as supports for enzymes. when a model enzyme, candida rugosa lipase, was encapsulated in peptide nanotubes, the catalytic activity of nanotube-bound lipases was increased 33% as compared to free-standing lipases at room temperature. at an elevated temperature, 65 degrees ...200516287245
recovery of sterols as fatty acid steryl esters from waste material after purification of tocopherols.tocopherols are purified industrially from soybean oil deodorizer distillate by a process comprising distillation and ethanol fractionation. the waste material after ethanol fractionation (tc waste) contains 75% sterols, but a purification process has not yet been developed. we thus attempted to purify sterols by a process including a lipase-catalyzed reaction. candida rugosa lipase efficiently esterified sterols in tc waste with oleic acid (oa). after studying several factors affecting esterifi ...200415638248
the acetates of p-nitrophenyl alpha-l-arabinofuranoside--regioselective preparation by action of lipases.all possible di-o-acetates and mono-o-acetates of p-nitrophenyl alpha-l-arabinofuranoside were prepared by chemoenzymatic way using lipases. the 2,3-di-o-acetate was obtained in 90% yield by deacetylation of the primary acetyl group of per-o-acetylated p-nitrophenyl alpha-l-arabinofuranoside by candida cylindracea lipase (ccl) or candida rugosa lipase (lay). the 2,5- and 3,5-di-o-acetates were obtained by acetylation of p-nitrophenyl alpha-l-arabinofuranoside by pseudomonas cepacia lipase (lps-3 ...200616288881
process modeling of the lipase-catalyzed dynamic kinetic resolution of (r, s)-suprofen 2,2,2-trifluoroethyl thioester in a hollow-fiber membrane.a candida rugosa lipase immobilized on polypropylene powder was employed as the biocatalyst for the enantioselective hydrolysis of (r, s)-suprofen 2,2,2-trifluorothioester in cyclohexane, in which trioctylamine was added as the catalyst to perform in situ racemization of the remaining (r)-thioester. a hollow-fiber membrane was also integrated with the dynamic kinetic resolution process in order to continuously extract the desired (s)-suprofen into an aqueous solution containing naoh. a kinetic m ...200415645310
a supported liquid membrane encapsulating a surfactant-lipase complex for the selective separation of organic acids.we have developed a novel, lipase-facilitated, supported liquid membrane (slm) for the selective separation of organic acids by encapsulating a surfactant-lipase complex in the liquid membrane phase. this system exhibited a high transport efficiency for 3-phenoxypropionic acid and enabled the selective separation of organic acids due to the different solubilities of the acids in the organic phase and the variable substrate specificity of the surfactant-lipase complex in the liquid membrane phase ...200515645485
immobilization of candida rugosa lipase on chitosan with activation of the hydroxyl groups.a method for immobilization of candida rugosa lipase to two types of chitosan beads by activating the hydroxyl groups of chitosan using carbodiimide coupling agent has been successfully developed. the ability of carbodiimide to activate the hydroxyl groups of chitosan was confirmed using the electron spectroscopy for chemical analysis (esca) technique. the properties of lipase immobilized using dry and wet chitosan beads were also investigated and compared. immobilization enhanced the enzyme sta ...200414585707
characterization and utilization of candida rugosa lipase immobilized on controlled pore silica.candida rugosa lipase was immobilized by covalent binding on controlled pore silica (cps) using glutaraldehyde as cross-linking agent under aqueous and nonaqueous conditions. the immobilized c. rugosa was more active when the coupling procedure was performed in the presence of a nonpolar solvent, hexane. similar optima ph (7.5-8.0) was found for both free and immobilized lipase. the optimum temperature for the immobilized lipase was about 10 degrees c higher than that for the free lipase. the th ...199915304694
application of sscp-pcr fingerprinting to profile the yeast community in raw milk salers cheeses.bacteria and yeasts are important sensory factors of raw-milk cheeses as they contribute to the sensory richness and diversity of these products. the diversity and succession of yeast populations in three traditional registered designation of origin (r.d.o.) salers cheeses have been determined by using phenotypic diagnoses and single-strand conformation polymorphism (sscp) analysis. isolates were identified by phenotypic tests and the sequencing of the d1-d2 domains of the 26s rrna gene. ninety- ...200616464699
lipase immobilized on poly(vp-co-hema) hydrogel for esterification reaction.lipase from candida rugosa was immobilized by entrapment on poly(n-vinyl- 2-pyrrolidone-co-2-hydroxyethyl methacrylate) (poly[vp-co-hema]) hydrogel, and divinylbenzene was the crosslinking agent. the immobilized enzymes were used in the esterification reaction of oleic acid and butanol in hexane. the activities of the immobilized enzymes and the leaching ability of the enzyme from the support with respect to the different compositions of the hydrogels were investigated. the thermal, solvent, and ...199915304777
ethyl oleate synthesis using candida rugosa lipase in a solvent-free system. role of hydrophobic interactions.the solvent-free esterification reaction of a commercial oleic acid and ethanol was selected as the test reaction for candida rugosa lipase immobilized on polypropylene (pp) at 318 k (initial molar ratio 1:1). adding of water from 0 to 30 wt. % (in gram per gram of fatty acid x 100) and the pretreatment of candida rugosa lipase with polyethylenglycol (peg), octane, and acetone increases the conversion to ethyl esters. the role of hydrophobic interactions of the lipase with pp and peg was studied ...200415360295
lipase-catalyzed esterification of 2-monoricinolein for 1,2 (2,3)-diricinolein synthesis.the purpose of this investigation was to develop conditions for producing 2-monoricinoleoyl dag. we used lipase-catalyzed hydrolysis of triricinolein to obtain 2-monoricinolein and thereafter synthesized 1,2(2,3)-diricinolein through esterification of 2-monoricinolein, using ricinoleic acid as the acyl donor. five different 1,3-specific immobilized lipases were tested for the initial methanolysis reaction: candida antarctica type b, rhizomucor miehei, rhizopus oryzae (rol), thermomyces lanuginos ...200616555475
kinetic resolution of ibuprofen catalyzed by candida rugosa lipase in ionic liquids.candida rugosa lipase-catalyzed esterification of ibuprofen with 1-propanol was conducted in seven ionic liquids and the results were compared with those in isooctane. although the enzyme showed comparable or higher activity in some ionic liquids compared to that in isooctane, only in the case of [bmim]pf6 was the enantioselectivity (e = 24.1) almost twice that (e = 13.0) of isooctane. in another six ionic liquids the enzyme enantioselectivity was much poorer (e = 1.1-6.4). at the same conversio ...200515515047
synthesis of structured lipids containing medium-chain and omega-3 fatty acids.the ability of different lipases to incorporate omega3 fatty acids, namely, eicosapentaenoic acid (epa, c20:5n-3), docosapentaenoic acid (dpa, c22:5n-3), and docosahexaenoic acid (dha, c22:6n-3), into a high-laurate canola oil, known as laurical 35, was studied. lipases from mucor miehei (lipozyme-im), pseudomonas sp. (ps-30), and candida rugosa (ay-30) catalyzed optimum incorporation of epa, dpa, and dha into laurical 35, respectively. other lipases used were candida anatrctica (novozyme-435) a ...200616756372
adsorption and activity of candida rugosa lipase on polypropylene hollow fiber membrane modified with phospholipid analogous polymers.efforts have recently been made toward the study of interactions of phospholipid with various enzymes. it seems that phospholipids may be directly involved in regulating the enzyme activity. in this work, three phospholipid analogous polymers (paps), containing hydrophobic octyloxy, dodecyloxy, and octadecyloxy groups (abbreviated as 8-pap, 12-pap, and 18-pap, respectively), were tethered on polypropylene hollow fiber microfiltration membrane (pphfmm) to create a biocompatible interface for lipa ...200415518509
on the estimation of the pseudo-stoichiometric matrix for macroscopic mass balance modelling of biotechnological processes.in this paper we propose a methodology to determine the structure of the pseudo-stoichiometric coefficient matrix kappa in a macroscopic mass balance based model. the first step consists in estimating the minimal number of reactions that must be taken into account to represent the main mass transfer within the bioreactor. this provides the dimension of kappa. then we discuss the identifiability of the components of kappa and we propose a method to estimate their values. finally we present a meth ...200415681276
an extracellular carboxylesterase from the basidiomycete pleurotus sapidus hydrolyses xanthophyll esters.an extracellular enzyme capable of efficient hydrolysis of xanthophyll esters was purified from culture supernatants of the basidiomycete pleurotus sapidus. under native conditions, the enzyme exhibited a molecular mass of 430 kda, and sds-page data suggested a composition of eight identical subunits. biochemical characterisation of the purified protein showed an isoelectric point of 4.5, and ideal hydrolysis conditions were observed at ph 5.8 and 40 degrees c. partial amino acid sequences were ...200515927887
rational strategy for the production of new crude lipases from candida rugosa.candida rugosa was cultured using different inducers (oleic acid, olive oil, sunflower oil, n-dodecanol and glycerol) as the only carbon source in batch conditions, as well as in several fed-batch fermentations (oleic acid as inducer) at variable feed rate conditions. the n-terminal analysis of each crude lipase revealed that, while the isoenzymes lip2 and lip3 are always secreted (at different proportions depending on the inducer), lip1 was produced only using n-dodecanol (batch conditions) or ...200515928857
efficient production of active recombinant candida rugosa lip3 lipase in pichia pastoris and biochemical characterization of the purified enzyme.candida rugosa lipase (crl), an important industrial enzyme, possesses several different isoforms encoded by the high-identity lip gene family (lip1 to lip7). in this study, an additional n-terminal peptide in front of the lip3 gene was removed by pcr, and the 18 nonuniversal serine codons (ctg) of the lip3 gene were converted into universal serine codons (tct) by means of an overlap extension pcr-based multiple-site-directed mutagenesis to express an active recombinant lip3 in the yeast pichia ...200616881684
glutaraldehyde cross-linking of lipases adsorbed on aminated supports in the presence of detergents leads to improved performance.lipases from candida rugosa (crl) and lipase isoforms a and b from candida antarctica (cal-a and cal-b) were adsorbed on aminated supports in the presence of detergents to have individual lipase molecules. then, one fraction was washed to eliminate the detergent, and both preparations were treated with glutaraldehyde. the presence of detergent during the cross-linking of the lipases to the support permitted an increase in the recovered activity (in some instances, even by a 10-fold factor). this ...200616961324
candida rugosa, an emerging fungal pathogen with resistance to azoles: geographic and temporal trends from the artemis disk antifungal surveillance program.candida rugosa is a fungus that appears to be emerging as a cause of infection in some geographic regions. we utilized the extensive database of the artemis disk antifungal surveillance program to describe the geographic and temporal trends in the isolation of c. rugosa from clinical specimens and the in vitro susceptibilities of 452 isolates to fluconazole and voriconazole. c. rugosa accounted for 0.4% of 134,715 isolates of candida, and the frequency of isolation increased from 0.03% to 0.4% o ...200617021085
increased enantioselectivity and remarkable acceleration of lipase-catalyzed transesterification by using an imidazolium peg-alkyl sulfate ionic liquid.several types of imidazolium salt ionic liquids were prepared derived from poly(oxyethylene)alkyl sulfate and used as an additive or coating material for lipase-catalyzed transesterification in an organic solvent. a remarkably increased enantioselectivity was obtained when the salt was added at 3-10 mol % versus substrate in the burkholderia cepacia lipase (lipase ps-c)-catalyzed transesterification of 1-phenylethanol by using vinyl acetate in diisopropyl ether or a hexane solvent system. in par ...200617029309
acidolysis and glyceride synthesis reactions using fatty acids with two pseudomonas lipases having different substrate specificities.enzymatic acidolysis and glyceride synthesis using polyunsaturated fatty acids (pufas) with lipases from pseudomonas fluorescens hu380 (hu-lipase), p. fluorescens ak102 (ak-lipase), and candida rugosa (cr-lipase) were studied. the acidolysis of triolein with eicosapentaenoic acid (epa) or docosahexaenoic acid (dha) in n-hexane was evaluated with lipases immobilized on celite 545. hu-lipase showed the highest incorporation rate at a low temperature (10 degrees c) with either epa or dha as the acy ...200617046530
utilizing hydrolases of opposite enantiopreference for the preparation of both enantiomers of (1r,7ar)-(-)- and (1s,7as)-(+)-3,6,7,7a-tetrahydro-1-hydroxy-7a-methyl-1h-inden-5(2h)-one.four racemic esters of (1r*,7ar*)-3,6,7,7a-tetrahydro-1-hydroxy-7a-methyl-1h-inden-5(2h)-one were prepared and subjected to hydrolysis with two types of hydrolases, including alcalase and three lipases. alcalase and lipase showed opposite enantiopreference on these esters. based on this result, we developed a gram-scale procedure using butanoate as the substrate, which was treated consecutively with alcalase and lipase from candida rugosa (crl), to give both enantiomers of the title compound in ...200415034910
identification of reaction networks for bioprocesses: determination of a partially unknown pseudo-stoichiometric matrix.in this paper we propose a methodology to determine the structure of the pseudo-stoichiometric coefficient matrix k in a mass balance-based model and to identify its coefficients from a set of available data. the first stage consists in estimating the number of reactions that must be taken into account to represent the main mass transfer within the bioreactor. this provides the dimension of k. then we propose a method to directly determine the structure of the matrix (i.e. mainly its zeros and t ...200515995850
kinetic resolution of (+/-)-1-phenylethanol in [bmim][pf6] using high activity preparations of lipases.lipases from two different sources candida rugosa (crl) and burkholderia cepacia (bcl) were formulated as enzyme precipitated and rinsed with organic solvents, organic solvent rinsed enzyme preparation, cross-linked enzyme aggregates (cleas) and protein coated micro-crystals (pcmcs). these various enzyme formulates were evaluated for the kinetic resolution of (+/-)-1-phenylethanol in ionic liquid [bmim][pf(6)] by transesterification with vinyl acetate. of all the enzyme forms evaluated eprp and ...200717157018
antifungal susceptibility of 1000 candida bloodstream isolates to 5 antifungal drugs: results of a multicenter study conducted in são paulo, brazil, 1995-2003.we evaluated all candida sp. bloodstream isolates obtained from patients admitted to 4 tertiary care hospitals between 1995 and 2003 in the city of são paulo, brazil. susceptibility to amphotericin b, 5-fluorocytosine, fluconazole (fcz), itraconazole (itz), and voriconazole (vcz) was determined using the clinical laboratory standards institute broth microdilution method. we tested a total of 1000 strains, including 400 strains of candida albicans (40%), 243 of candida tropicalis (24.3%), 238 of ...200717240110
a novel reactive perstraction system based on liquid-core microcapsules applied to lipase-catalyzed biotransformations.a novel reactive perstraction system has been developed based on liquid-core capsules, involving an enzyme-catalyzed reaction coupled with simultaneous in situ product recovery. lipase-catalyzed reactions, hydrolysis of triprionin and nitrophenyl laurate, were selected to test the system and demonstrate the feasibility of immobilization of enzymes to the membranes of liquid-core capsules and the ability to extract hydrophobic products of the reaction within the capsule core. the lipase from cand ...200616136589
highly active, lipase silicone elastomers.lipase candida rugosa was entrapped in silicone rubber via condensation-cure room temperature vulcanization of silanol-terminated poly(dimethylsiloxane) with tetraethyl orthosilicate as a crosslinker, to give a highly active silicone-enzyme elastomer. the effect on enzyme activity of addition of water and hydrophilic polymeric moieties based on poly(ethylene oxide) 2 was examined, as were crosslinker concentration, enzyme concentration, and elastomer thickness. it was demonstrated that lipase is ...200515576139
transport of organic acids through a supported liquid membrane driven by lipase-catalyzed reactions.we have developed a lipase-facilitated supported liquid membrane. lipase-catalyzed reactions were coupled with a supported liquid membrane (slm) to transport organic acids through the slm. we succeeded in the rational transport of organic acids through the slm using lipase-catalyzed reactions and observed that there were differences in the transport behavior of various organic acids due to the substrate specificity of lipase. subsequently, various parameters, such as the alcohol concentration in ...200316233539
acidolysis of tristearin with selected long-chain fatty acids.five lipases, namely, candida antarctica (novozyme-435), mucor miehei (lipozyme-im), pseudomonas sp. (ps-30), aspergillus niger (ap-12), and candida rugosa (ay-30), were screened for their effect on catalyzing the acidolysis of tristearin with selected long-chain fatty acids. among the lipases tested c. antarctica lipase catalyzed the highest incorporation of oleic acid (oa, 58.2%), gamma-linolenic acid (gla, 55.9%), eicosapentaenoic acid (epa, 81.6%), and docosahexaenoic acid (dha, 47.7%) into ...200717288439
structural effects of amphiphiles on candida rugosa lipase activation by freeze-drying of aqueous solution of enzyme and amphiphile.lipases co-lyophilized with water-soluble gemini-type amphiphiles were found to have high enzyme activity in nonaqueous media without washing out of the amphiphile with anhydrous organic solvent. in this study, we obtained freeze-dried complexes of candida rugosa lipase (crl) with six water-soluble twin glusitol-headed amphiphiles bearing different types of hydrophobic tails, including newly synthesized ones, and their transesterification activity in organic solvent was evaluated. the results in ...200316233568
inhibition of rhizomucor miehei and candida rugosa lipases by d-glucose in esterification between l-alanine and d-glucose.a detailed kinetic study of the esterification of d-glucose with l-alanine catalyzed by lipases from rhizomucor miehei (rml) and candida rugosa (crl) showed that both lipases follow the ping-pong bi-bi mechanism, in which l-alanine and d-glucose bind in subsequent steps releasing water and l-alanyl-d-glucose, with competitive substrate inhibition by d-glucose at higher concentrations leading to the formation of dead-end lipase.d-glucose complexes. an attempt to obtain the best fit of this kineti ...200717368393
frequent analytical/experimental problems in lipase-mediated synthesis in solvent-free systems and how to avoid them.compared with chemical catalysis, enzymatic catalysis is a relatively new topic. experimental work involving lipases deserves careful attention and accurate procedures still need to be implemented. a rapid but careful survey of published data immediately demonstrates that experiments performed under similar conditions with similar reagents have led to very different results. the aim of this work is to point out the importance of accurate and systematic procedures in order to ensure the reproduci ...200515789246
partially purified carica papaya lipase: a versatile biocatalyst for the hydrolytic resolution of (r,s)-2-arylpropionic thioesters in water-saturated organic solvents.with the hydrolytic resolution of (r,s)-naproxen 2,2,2-trifluoroethyl thioesters in water-saturated isooctane as a model system, improvements of the specific lipase activity and thermal stability were found when a crude carica papaya lipase (cpl) was partially purified and employed as the biocatalyst. the partially purified carica papaya lipase (pcpl) was furthermore explored as an effective enantioselective biocatalyst for the hydrolytic resolution of (r,s)-profen thioesters in water-saturated ...200515918166
multiple mutagenesis of the candida rugosa lip1 gene and optimum production of recombinant lip1 expressed in pichia pastoris.candida rugosa lipase, a significant catalyst, had been widely employed to catalyze various chemical reactions such as non-specific, stereo-specific hydrolysis and esterification for industrial biocatalytic applications. several isozymes encoded by the lip gene family, namely lip1 to lip7, possess distinct thermal stability and substrate specificity, among which the recombinant lip1 showed a distinguished catalytic characterization. in this study, we utilized pcr to remove an unnecessary linker ...200415592826
prospective observational study of candidemia in são paulo, brazil: incidence rate, epidemiology, and predictors of mortality.studies conducted in tertiary care hospitals of different european countries and the united states have shown incidence rates of candidemia ranging from 0.17 to 0.76 and 0.28 to 0.96 per 1,000 admissions, respectively. so far, only 1 study has evaluated the incidence rates of candidemia in tertiary care hospitals in latin american countries.200717464917
internal transcribed spacer sequencing versus biochemical profiling for identification of medically important yeasts.in this study, we established an in-house database of yeast internal transcribed spacer (its) sequences. this database includes medically important as well as colonizing yeasts that frequently occur in the diagnostic laboratory. in a prospective study, we compared molecular identification with phenotypic identification by using the id32c system (biomérieux) for yeast strains that could not be identified by a combination of chromagar candida and morphology on rice agar. in total, 113 yeast strain ...200616390952
altering the substrate specificity of candida rugosa lip4 by engineering the substrate-binding sites.candida rugosa (formerly candida cylindracea) lipase (crl) is an important industrial enzyme that is widely used in biotechnological applications such as the production of fatty acids and the synthesis of various esters. crl comprises at least seven isozymes (lip1-lip7), which share a similar amino acid sequence but with different specificities for substrates. previously, lip4 was reported to have higher esterase activity toward long acyl-chain ester and lower lipase activity toward triglyceride ...200717536826
peptidase profiles from non-albicans candida spp. isolated from the blood of a patient with chronic myeloid leukemia and another with sickle cell disease.candida lipolytica and candida rugosa were isolated from blood samples from a patient with chronic myeloid leukemia (31 years old) and a patient with sickle cell disease (1-year-old), respectively. isolates were grown for 48 h at 37 degrees c in either sabouraud or tryptone soy broth (tsb). peptidases were tested for using substrate sodium dodecyl sulfate-polyacrylamide gels with gelatin, casein, bovine serum albumin (bsa) or hemoglobin. enzymography analyses were made on the following substrate ...200717559410
codon optimization of candida rugosa lip1 gene for improving expression in pichia pastoris and biochemical characterization of the purified recombinant lip1 lipase.an important industrial enzyme, candida rugosa lipase (crl) possesses several different isoforms encoded by the lip gene family (lip1-lip7), in which the recombinant lip1 is the major form of the crl multigene family. previously, 19 of the nonuniversal serine codons (ctg) of the lip1 gene hav been successfully converted into universal serine codons (tct) by overlap extension pcr-based multiple-site-directed mutagenesis to express an active recombinant lip1 in the yeast pichia pastoris. to improv ...200616448188
chitosan-tethered poly(acrylonitrile-co-maleic acid) hollow fiber membrane for lipase immobilization.a protocol was used to prepare a dual-layer biomimetic membrane as support for enzyme immobilization by tethering chitosan on the surface of poly(acrylonitrile-co-maleic acid) (pancma) ultrafiltration hollow fiber membrane in the presence of 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride (edc)/n-hydroxylsuccin-imide (nhs). the chemical change of the chitosan-modified pancma membrane surface was confirmed with fourier transform infrared spectroscopy and x-ray photoelectron spectroscop ...200515919112
atomic force microscope studies on the interactions of candida rugosa lipase and supported lipidic bilayers.using the langmuir-blodgett technique we prepared substrate supported well-defined lipid/phospholipid (1-mono-palmitoyl-rac-glycerol (mpg)/l,2-dipalmitoyl-sn-glycerol-3-phosphocholine (dppc)) bilayers in which the mpg lipid leaflet was exposed to the aqueous phase. hydrolysis of mpg performed by candida rugosa lipase (crl) on the upper mpg layer of these supported bilayers on mica was imaged by real time atomic force microscope (afm) using a liquid cell, so that the area increase of the initial ...200616829060
studies of reaction parameters on synthesis of citronellyl laurate ester via immobilized candida rugosa lipase in organic media.immobilized candida rugosa lipase was used for the synthesis of citronellyl laurate from citronellol and lauric acid. screening of different types of support (amberlite mb-1 and celite) for immobilization of lipase and solvent (n-hexane, n-heptane, and iso-octane) and optimization of reaction conditions, such as catalyst loading, effect of substrates molar ratio and temperature, have been studied. the maximum enzyme activity was obtained at 310 k. the immobilized c. rugosa lipase onto amberlite ...200616868763
optimization of medium composition for lipase production by candida rugosa ncim 3462 using response surface methodology.a sequential optimization approach using statistical design of experiments was employed to enhance the lipase production by candida rugosa in submerged batch fermentation. twelve medium components were evaluated initially using the plackett-burman 2-level factorial design. the significant variables affecting lipase production were found to be glucose, olive oil, peptone, (nh4)2so4, and fecl3.6h2o. various vegetable oils were tested in the second step, and among them, groundnut oil was found to b ...200717668023
investigating ph and cu (ii) effects on lipase activity and enantioselectivity via kinetic and spectroscopic methods.for candida rugosa lipase (crl) catalyzed hydrolysis of racemic 1-phenethyl acetate, both the weakly acidic ph (ph 6.0) and the addition of 1 mm copper (ii) ion enhanced the enzyme activity and enantioselectivity (e value) about twofold, as compared with that under neutral ph and noadditive conditions. the decrease of activation free energy (deltag) and increase of k(cat)(r)/k(cat)(s) at weakly acidic ph and/or in the presence of copper (ii) characterized the kinetic behavior of crl. on the othe ...200617068757
studies of optimum conditions for covalent immobilization of candida rugosa lipase on poly(gamma-glutamic acid) by rsm.poly(gamma-glutamic acid) (gamma-pga) is a material of polymer. immobilization of candida rugosa lipase (lipase ay-30) by covalent binding on gamma-pga led to a markedly improved performance of the enzyme. response surface methodology (rsm) and 3-level-3-factor fractional factorial design were employed to evaluate the effects of immobilization parameters, such as immobilization time (2-6h), immobilization temperature (0-26 degrees c), and enzyme/support ratio (0.1-0.5, w/w). based on the analysi ...200817706421
a water activity control system for enzymatic reactions in organic media.a water activity control system for enzymatic synthesis in organic media, for litre-scale reactors has been constructed. water activity, a(w), is a key factor when using enzymes in non-conventional media and the optimum value varies for different enzymes. the control system consists of a water activity sensor in the headspace of a jacketed glass reactor (equipped with narrow steel tubes to introduce air), gas-washing bottles containing blue silica gel (a(w)=0) and water (a(w)=1), a pc to monitor ...200717096388
hofmeister effects in enzymatic activity: weak and strong electrolyte influences on the activity of candida rugosa lipase.the effects of weak and strong electrolytes on the enzymatic activity of candida rugosa lipase are explored. weak electrolytes, used as buffers, set the ph, while strong electrolytes regulate the ionic strength. the interplay between ph and ionic strength has been assumed to be the determinant of enzymatic activity. in experiments that probe activities by varying these parameters, there has been little attention focused on the role of specific electrolyte effects. here we show that both buffers ...200717266269
lipolytic enzymes with improved activity and selectivity upon adsorption on polymeric nanoparticles.nanostructured polystyrene (ps) and polymethylmethacrylate (pmma) were used as carriers for the preparation of bioconjugates with lipolytic enzymes, such as candida rugosa lipase (crl) and pseudomonas cepacia lipase (pcl). simple addition of the lipase solution to the polymeric nanoparticles under protein-friendly conditions (ph 7.6) led to the formation of polymer-enzyme bioconjugates. energy filtered-transmission electron microscopy (ef-tem) performed on immuno-gold labeled samples revealed th ...200717803276
immobilization of candida rugosa lipase on a ph-sensitive support for enantioselective hydrolysis of ketoprofen ester.candida rugosa lipase (lipase of) was immobilized by covalent binding to a ph-sensitive support showing reversibly soluble-insoluble characteristics with ph change. the immobilized lipase could carry out the enantioselective hydrolysis of ketoprofen ester in a soluble form yet be recovered after precipitation by simply adjusting ph. its activity and enantioselectivity for hydrolysis of 2-chloroethyl ester of ketoprofen were enhanced 1.5-fold and 8.7-fold compared with those of free lipase. after ...200515748766
high-yield synthesis of wax esters catalysed by modified candida rugosa lipase.candida rugosa lipase (crl) was applied in a non-solvent esterification reaction to yield twelve wax esters. all products were obtained in nearly 100% yield for 10 h at 50 degrees c when immobilized peg(2000)-activated c. rugosa lipase was added to the reaction mixture. the surfactant had also a beneficial effect on the stability of the biocatalytic preparation with 83% of its activity conserved after the seventh run of repeated batch reactions.200817957342
enhancement of lipase activity in non-aqueous media upon immobilization on multi-walled carbon nanotubes.immobilization of biologically active proteins on nanosized surfaces is a key process in bionanofabrication. carbon nanotubes with their high surface areas, as well as useful electronic, thermal and mechanical properties, constitute important building blocks in the fabrication of novel functional materials.200718047656
a convenient preparation of 1,2,3-tri-o-acetyl-beta-d-ribofuranose by enzymatic regioselective 5-o-deacetylation of the peracetylated ribofuranose.the lipase from candida rugosa (sigma) was used to catalyze the regioselective deacetylation at the 5-position of 1,2,3,5-tetra-o-acetyl-beta-d-ribofuranose on a preparative scale. enzymatic deacetylation provides a convenient one-step preparation of 1,2,3-tri-o-acetyl-beta-d-ribofuranose.200415063214
lipase specificity towards eicosapentaenoic acid and docosahexaenoic acid depends on substrate structure.the fatty acid specificity of five lipases towards eicosapentaenoic acid (epa) and docosahexaenoic acid (dha) was evaluated in the hydrolysis of fish oil, squid oil and a model system. the model system contained methyl esters of epa, dha and palmitic acid. all the investigated lipases discriminated against both epa and dha more in the model system than in the natural oils. thus both epa and dha were more easily hydrolysed from a glyceride than from a methyl ester. in the model system, the lipase ...200818067872
impact of aluminum on the oxidation of lipids and enzymatic lipolysis in monomolecular films at the air/water interface.there is evidence that serious pathologies are associated with aluminum (al). in the present work, the influence of al on enzymatic lipolysis was studied with the aim to get more insight into the possible link between the al-induced membrane modification and the cytotoxicity of the trivalent cation (aliii). lipid monolayers were used as model membranes. the monomolecular film technique allowed monitoring the al-dependent modifications of the lipid monolayer properties and enzyme kinetics. two en ...200717279785
a method for lipase co-precipitation in a biodegradable protein matrix.this article presents a novel method for immobilization of active ingredients. the method is based on co(2) aided active ingredient co-precipitation with glycinin, a biodegradable protein matrix from edible soybean protein. glycinin precipitates abundantly under isoelectric conditions and serves as the matrix within which the active substance is trapped during the precipitation process. the enzyme lipase from candida rugosa was successfully co-precipitated into the protein pellet to prove the pr ...200717514752
understanding candida rugosa lipases: an overview.candida rugosa lipase (crl) is one of the enzymes most frequently used in biotransformations. however, there are some irreproducibility problems inherent to this biocatalyst, attributed either to differences in lipase loading and isoenzymatic profile or to other medium-engineering effects (temperature, a(w), choice of solvent, etc.). in addition, some other properties (influence of substrate and reaction conditions on the lid movement, differences in the glycosylation degree, post-translational ...200616288844
promoter analysis and differential expression of the candida rugosa lipase gene family in response to culture conditions.five lipase genes have been identified and sequenced from candida rugosa. however, as the sequences of lip multigene family are extremely closely related, it is difficult to characterize the expression spectrum of lip genes. in the present work we have cloned, sequenced, and analyzed the promoters of these five lip isoform genes, and several putative transcriptional elements including oleate response element (ore) and upstream activation sequence 1 (uas1) were identified. a quantitative real-tim ...200818290622
ph memory of immobilized lipase for (+/-)-menthol resolution in ionic liquid.magnetic deae-gma-edma microspheres were prepared via suspension polymerization and used for the immobilization of candida rugosa lipase by ion exchange. the effect of ph values on the immobilization of lipase was investigated. resolution of (+/-)-menthol in the hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate was performed by immobilized lipase-catalyzed enantioselective esterification with propionic anhydride as acyl donor. the effects of ph condition at lipase immobili ...200818338863
a secreted lipase encoded by lip1 is necessary for efficient use of saturated triglyceride lipids in fusarium graminearum.a triglyceride lipase gene lip1 was identified in the genome of fusarium graminearum strain ph-1. the predicted protein encoded by lip1 contains 591 amino acid residues with a putative n-terminal signal peptide and shows 57 and 40-44 % identity to a botrytis cinerea lipase and five candida rugosa lipases, respectively. yeast cells overexpressing lip1 showed lipolytic activity against a broad range of triglyceride substrates. northern blot analyses revealed that expression of lip1 was activated i ...200516339936
blue native electrophoresis study on lipases.we have developed a modified blue native polyacrylamide gel electrophoresis (page) protocol that can overcome aggregation of lipases seen in native page. we have shown that two lipases, pseudomonas aeruginosa lipase and candida rugosa lipase, which aggregate in the native gel, can be resolved using our protocol. activity staining was done to test for the functionality of the two lipases.200818381198
microscopic analysis of ester hydrolysis reaction catalyzed by candida rugosa lipase.the relationship between the kinetics of the lipase-catalyzed oil hydrolysis and the surface area distribution of oil droplets was investigated using ethyl decanoate and gum arabic (ga) as a model oil and an emulsifier, respectively. along an ethyl decanoate concentration gradient between 2 and 8 mm, the initial hydrolysis rate increased at 0.25% (w/v) ga but did not change at 1.0% (w/v) ga. at 0.25% ga, the surface area of droplets was narrowly distributed regardless of the ethyl decanoate conc ...200616406517
monoglycerides and diglycerides synthesis in a solvent-free system by lipase-catalyzed glycerolysis.five lipases were screened (thermomyces lanuginosus free and immobilized forms, candida antarctica b, candida rugosa, aspergillus niger, and rhizomucor miehei) to study their ability to produce monoglycerides (mg) and diglycerides (dg) through enzymatic glycerolysis of soybean oil. lipase from c. antarctica was further studied to verify the enzyme load (wt% of oil mass), the molar ratio glycerol/oil, and the water content (wt% of glycerol) on the glycerolysis reaction. the best dg and mg product ...200818421596
pre-treatment of high oil and grease pet food industrial wastewaters using immobilized lipase hydrolyzation.wastewaters generating from pet food industries contain high concentration of oil and grease (o&g), which is difficult to treat through conventional biological treatment systems. in this study, the hydrolysis of o&g originating from pet food industrial wastewater was evaluated. candida rugosa lipase was immobilized in calcium alginate beads and applied in the hydrolysis experiment. results showed that approximately 50% of the o&g was hydrolyzed due to the enzyme activity. a significant increment ...200616504384
a chemoenzymatic approach to the synthesis of enantiomerically pure (s)-3-hydroxy-gamma-butyrolactone.optically pure (s)-3-hydroxy-gamma-butyrolactone, an important chiral building block in the pharmaceutical industry, was synthesized from l: -malic acid by combining a selective hydrogenation and a lipase-catalyzed hydrolysis. lipase from candida rugosa was found to be the most efficient enzyme for the hydrolysis of (s)-beta-benzoyloxy-gamma-butyrolactone. the use of organic solvent-aqueous two-phase system was employed to extract benzoic acid generated from enzymatic hydrolysis of the substrate ...200818446525
reusability of surfactant-coated candida rugosa lipase immobilized in gelatin microemulsion-based organogels for ethyl isovalerate synthesis.in our previous study, a surfactant-coated candida rugosa lipase immobilized in microemulsion-based organogels was exploited for the synthesis of ethyl isovalerate. in the present study, we are focusing on the effective reuse of lipase immobilized in microemulsion-based organogels (mbgs) in terms of retainment of the catalytic activity. as water is one of the co-products in esterification reactions, the removal of water becomes a priority to allow the reaction to work in the forward direction an ...200818467869
amphotericin b-metronidazole combination against candida spp.oropharyngeal candidiasis (opc) remains a common opportunistic infection in hiv-infected patients. candida albicans is the most frequent causative agent of opc. however, non-albicans spp. are being increasingly isolated. candidal cell wall proteins and mannoproteins play important roles in the biology and patogenesis of candidiasis. in the present study, we have analyzed the proteinaceous components associated with cell wall extracts from c. albicans, candida tropicalis, candida pseudotropicalis ...199818473531
[inhibition of lipase activity by low-molecular-weight chitosan].inhibition of enzymatic activity of lipase (ec 3.1.1.3) from the fungus candida rugosa and wheat (triticum aestivum l.) germ by low-molecular-weight chitosan with an average molecular weight of 5.7 kda in reactions of p-nitrophenyl palmitate cleavage was studied. preincubation of lipases with chitosan, prior to addition of the substrate to solution, showed that equilibrium during the lipase-inhibitor complex formation was reached within 30 min. the inhibition constants for c. rugosa lipase and w ...200818491595
preparation and characterization of chitosan membranes by using a combined freeze gelation and mild crosslinking method.when gelification is performed by freezing-thawing repeated cycles, the resultant gel-like polymer systems are called cryogels. this work aims to assess the effect of the addition of glutaraldehyde and 18 crown ether-6 on surface properties and protein loading of dried chitosan cryogel films. residual water content of treated chitosan membranes ranged between 11.93 and 13.86%, while their water activities vary from 0.5 to 0.7 (measured from 4 to 60 degrees c). based on thermal data, water evapor ...200918546023
efficient hydrolysis of tuna oil by a surfactant-coated lipase in a two-phase system.a surfactant-coated lipase (scl) prepared by mixing candida rugosa lipase with emulsifier in ethanol was used to hydrolyze tuna oil in a two-phase aqueous-organic system. both enzyme (scl) and substrate (tuna oil) were soluble in the organic phase, and the hydrolysis could occur with water molecules from the aqueous phase. this hydrolysis could promptly proceed compared to that catalyzed by native lipases which only occurred at the interface between the two phases. michaelis-menten kinetics in t ...200616506843
nanofibrous poly(acrylonitrile-co-maleic acid) membranes functionalized with gelatin and chitosan for lipase immobilization.nanofibrous membranes with an average diameter of 100 and 180 nm were fabricated from poly(acrylonitrile-co-maleic acid) (pancma) by the electrospinning process. these nanofibrous membranes contain reactive groups which can be used to covalently immobilize biomacromolecules. two natural macromolecules, chitosan and gelatin, were tethered on these nanofibrous membranes to fabricate dual-layer biomimetic supports for enzyme immobilization in the presence of 1-ethyl-3-(dimethyl-aminopropyl) carbodi ...200616584770
characteristics of immobilized lipase-catalyzed hydrolysis of olive oil of high concentration in reverse phase system.candida rugosa lipase immobilized by adsorption on swollen sephadex lh-20 could almost completely hydrolyze 60% (v/v) olive oil in isooctane. kinetic analysis of the lipase-catalyzed hydrolysis reaction was found to be possible in this system. amount of fatty acids produced was linearly proportional to the enzyme concentration of 720 microg/g wet gel. the specific enzyme activity was 217 units/mg protein at 60% (v/v) olive oil concentration. when the initial rate is plotted versus concentration ...198918587887
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