Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| highly efficient preparation of lipophilic hydroxycinnamates by solvent-free lipase-catalyzed transesterification. | various medium- or long-chain alkyl cinnamates and hydroxycinnamates, including oleyl p-coumarate as well as palmityl and oleyl ferulates, were prepared in high yield by lipase-catalyzed transesterification of an equimolar mixture of a short-chain alkyl cinnamate and a fatty alcohol such as lauryl, palmityl, and oleyl alcohol under partial vacuum at moderate temperature in the absence of solvents and drying agents in direct contact with the reaction mixture. immobilized lipase b from candida ant ... | 2006 | 16968063 |
| lipase-catalyzed reactions at different surfaces. | starting from gold chips, we have tailor-made three surfaces by the self-assembly monolayer technique: one entirely hydrophobic, one hydrophobic with dispersed carboxyl groups, and one hydrophilic, containing hydroxyl groups. rhizomucor miehei lipase has been adsorbed to the hydrophobic and the hydrophilic surfaces and covalently bound to the surface containing carboxyl groups. the adsorption of two substrates-capric acid (decanoic acid) and monocaprin-on the lipase-covered surfaces was monitore ... | 2006 | 16952258 |
| adverse effect of chloride impurities on lipase-catalyzed transesterifications in ionic liquids. | the adverse influence of chloride impurities on the lipase-catalyzed transesterification in ionic liquid is described. the activity of lipase from rhizomucor miehei exponentially decreased with increasing cl(-) content in 1-octyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] amide, [omim][tf(2)n], and the activity of lipase in [omim][tf(2)n] mixture containing 2% [omim] [cl] was only about 2% of the activity in pure [omim][tf(2)n]. the activity of lipase from candidantarctica linearly decre ... | 2006 | 16820978 |
| characteristics of structured lipid prepared by lipase-catalyzed acidolysis of roasted sesame oil and caprylic acid in a bench-scale continuous packed bed reactor. | structured lipid (sl) was prepared from roasted sesame oil and caprylic acid (ca) by rhizomucor miehei lipase-catalyzed acidolysis in a bench-scale continuous packed bed reactor. total incorporation and acyl migration of ca in the sl were 42.5 and 3.1 mol %, respectively, and the half-life of the lipase was 19.2 days. the sl displayed different physical and chemical properties, less saturated dark brown color, lower viscosity, lower melting and crystallization temperature ranges, higher melting ... | 2006 | 16819927 |
| optimisation of n-octyl oleate enzymatic synthesis over rhizomucor miehei lipase. | octyl oleate is a useful organic compound with several applications in cosmetic, lubricant and pharmaceutical industry. at first, the enzymatic synthesis of n-octyl oleate by direct lipase-catalysed esterification of oleic acid and 1-octanol was investigated in a stirred batch reactor in solvent-free system. a systematic screening and optimisation of the reaction parameters were performed to gain insight into the kinetics mechanism. particularly, enzyme concentration, reaction temperature, stirr ... | 2006 | 16770594 |
| 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 ... | 2006 | 16756372 |
| antifungal and antibacterial activities of araucaria araucana (mol.) k. koch heartwood lignans. | five lignans (secoisolariciresinol, pinoresinol, eudesmin, lariciresinol, and lariciresinol-4-methyl ether) were isolated from an meoh extract from araucaria araucana (mol.) k. koch wood for the first time in this species and their structures determined with spectroscopic methods. the antimicrobial activities of these compounds were determined for the bacteria citrobacter sp., bacillus subtilis, escherichia coli, micrococcus luteus, staphylococcus aureus, and pseudomonas aeruginosa, and for the ... | 2006 | 16610214 |
| solvent-free lipase-catalyzed preparation of long-chain alkyl phenylpropanoates and phenylpropyl alkanoates. | an enzymatic method was developed for the preparation of medium- or long-chain alkyl 3-phenylpropenoates (alkyl cinnamates), particularly alkyl hydroxy- and methoxy-substituted cinnamates such as oleyl p-coumarate and oleyl ferulate. the various alkyl cinnamates were formed in high to moderate yield by lipase-catalyzed esterification of cinnamic acid and its analogues with fatty alcohols in vacuo at moderate temperatures in the absence of drying agents and solvents. immobilized candida antarctic ... | 2006 | 16608217 |
| dialkyl 3,3'-thiodipropionate and dialkyl 2,2'-thiodiacetate antioxidants by lipase-catalyzed esterification and transesterification. | medium- and long-chain dialkyl 3,3'-thiodipropionate antioxidants such as dioctyl 3,3'-thiodipropionate, didodecyl 3,3'-thiodipropionate, dihexadecyl 3,3'-thiodipropionate, and di-(cis-9-octadecenyl) 3,3'-thiodipropionate were prepared in high yield by lipase-catalyzed esterification and transesterification of 3,3'-thiodipropionic acid and its dimethyl ester, respectively, with the corresponding medium- or long-chain 1-alkanols, i.e., 1-octanol, 1-dodecanol, 1-hexadecanol, and cis-9-octadecen-1- ... | 2006 | 16608215 |
| 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 ... | 2006 | 16555475 |
| angiotensin converting enzyme inhibitory activity of amino acid esters of carbohydrates. | l-alanyl-d-glucose, l-valyl-d-glucose, l-phenylalanyl-d-glucose and l-phenylalanyl-lactose esters were synthesized enzymatically using two lipases viz., rhizomucor miehei lipase (rml) and porcine pancreas lipase (ppl) and tested for their potential as inhibitors of angiotensin converting enzyme (ace) in vitro. the esters exhibited concentration related ace inhibitory activity. the potency of the various esters measured in terms of ic50 values were as follows: l-phenylalanyl-d-glucose, ic50-0.121 ... | 2006 | 16529809 |
| spectroscopic and catalytic studies of lipases in ternary hexane-1-propanol-water surfactantless microemulsion systems. | a series of water-in-oil microemulsion systems formulated without surfactant were used to solubilize lipases from rhizomucor miehei and candida antarctica b. the effect of the system's composition on the velocity of enzymic reactions was investigated following a model esterification reaction. the interaction between enzymes and the microemulsion environment was studied by steady state fluorescence spectroscopy. the site of localization of the enzyme within the different microdomains of the dispe ... | 2006 | 16364610 |
| [effect of chemical modification of lipase on the regulation of its lipolytic activity in reversed micelles]. | hydrophilized and hydrophobized forms of the lipase from mucor miehei were obtained by its chemical modification with cellobiose and n-hydroxysuccinimidyl palmitate with a modification degree of 4 in both cases. a comparative analysis of the regulation of the catalytic activities of the native and modified lipases was carried out in the system of reversed micelles of ot aerosol (aot) in isooctane. the level of catalytic activity of all the lipase preparations in the micellar medium was found to ... | 2005 | 16363131 |
| substrate specificity and kinetic properties of enzymes belonging to the hormone-sensitive lipase family: comparison with non-lipolytic and lipolytic carboxylesterases. | we have studied the kinetics of hydrolysis of triacylglycerols, vinyl esters and p-nitrophenyl butyrate by four carboxylesterases of the hsl family, namely recombinant human hormone-sensitive lipase (hsl), est2 from alicyclobacillus acidocaldarius, afest from archeoglobus fulgidus, and protein rv1399c from mycobacterium tuberculosis. the kinetic properties of enzymes of the hsl family have been compared to those of a series of lipolytic and non-lipolytic carboxylesterases including human pancrea ... | 2005 | 16325466 |
| adsorption of lipase on hollow fiber membrane chips. | the amount of lipase from mucor miehei adsorption on ultrafiltration polysulfone hollow fiber membrane chips has been determined using different lipase concentrations at three different temperatures, namely 30, 35, and 40 degrees c. it was experimentally shown that adsorption of lipase increases with temperature. the results were used to evaluate the constants found in the langmuir adsorption isotherm model coupled with the van't hoff's relationship. a temperature dependence correlation for the ... | 2005 | 16317961 |
| production of biodiesel by lipase-catalyzed transesterification of vegetable oils: a kinetics study. | kinetics of production of biodiesel by enzymatic methanolysis of vegetable oils using lipase has been investigated. a mathematical model taking into account the mechanism of the methanolysis reaction starting from the vegetable oil as substrate, rather than the free fatty acids, has been developed. the kinetic parameters were estimated by fitting the experimental data of the enzymatic reaction of sunflower oil by two types of lipases, namely, rhizomucor miehei lipase (rm) immobilized on ion-exch ... | 2005 | 16209548 |
| quantization of ph: evidence for acidic activity of triglyceride lipases. | here we present a study of lipolytic activity of lipases from fusarium solani pisi (cutinase), rhizomucor miehei, pseudomonas cepacia, and humicola lanuginosa. their activities toward triolein provide clear evidence for considerable enzymatic activity under acidic conditions. the activity was followed using fourier transform infrared attenuated total reflection (ftir-atr) and nuclear magnetic resonance (nmr). using these approaches, all the lipases that were studied exhibited lipolytic activity ... | 2005 | 16114894 |
| polyhydric alcohol protective effect on rhizomucor miehei lipase deactivation enhanced by pressure and temperature treatment. | the influence of polyhydric alcohols (sorbitol, xylitol, erythritol, glycerol) on the thermal stability of rhizomucor miehei lipase has been studied at high hydrostatic pressure (up to 500 mpa). in the absence of additives, a protective effect (pe) (the ratio between the residual activities determined at 480 mpa for the enzyme in the presence or absence of polyhydric alcohols) of low-applied pressures (from 50 mpa to 350 mpa) against thermal deactivations (at 50 degrees c and 55 degrees c) has b ... | 2005 | 16044285 |
| synthesis of acylglycerols from omega-3 fatty acids and conjugated linoleic acid isomers. | n-3 pufa (omega-3 polyunsaturated fatty acid) concentrate from mackerel oil enriched in epa (eicosapentaenoic acid) and dha (docosahexaenoic acid) was used to esterify isomers of cla (conjuated linoleic acid) to produce acylglycerols (glycerides). catalysis was potentiated by immobilized lipases from the yeast candida antarctica and the mould mucor miehei. c. antarctica lipase showed higher reactivity and much faster initial rate of incorporation of cla into acylglycerols than its m. miehei coun ... | 2006 | 16008528 |
| copolymeric polythioesters by lipase-catalyzed thioesterification and transthioesterification of alpha,omega-alkanedithiols. | linear copolymeric polythioesters [pte; poly(alpha,omega-alkanedioic acid-co-alpha,omega-alkanedithiols)] were formed in good yield (approximately 69%) by thioesterification of 1,12-dodecanedioic acid with 1,6-hexanedithiol and 1,8-octanedithiol, respectively, catalyzed by immobilized lipase from rhizomucor miehei (lipozyme rm im) in vacuo without a solvent. similarly, transthioesterification (thiolysis) of diethyl 1,12-dodecanedioate with 1,6-hexanedithiol led to the formation of approximately ... | 2006 | 16007456 |
| lipase-catalyzed acidolysis of tripalmitin with hazelnut oil fatty acids and stearic acid to produce human milk fat substitutes. | structured lipids (sls) containing palmitic, oleic, stearic, and linoleic acids, resembling human milk fat (hmf), were synthesized by enzymatic acidolysis reactions between tripalmitin, hazelnut oil fatty acids, and stearic acid. commercially immobilized sn-1,3-specific lipase, lipozyme rm im, obtained from rhizomucor miehei was used as the biocatalyst for the enzymatic acidolysis reactions. the effects of substrate molar ratio, reaction temperature, and reaction time on the incorporation of ste ... | 2005 | 15998148 |
| hydrolyzable nonionic surfactants: stability and physicochemical properties of surfactants containing carbonate, ester, and amide bonds. | a linear and a branched nonionic cleavable surfactants containing a carbonate bond have been prepared from tetra(ethylene glycol) and an alkylchloroformate. the stability of these carbonate surfactants was determined by investigating their hydrolysis and biodegradability characteristics. the hydrolysis was catalyzed by alkali or enzymes (esterase from porcine liver and lipases from mucor miehei and candida antarctica b) and was monitored using 1h nmr. it was found that the stability toward alkal ... | 2005 | 15979083 |
| acrylamide-quenching of rhizomucor miehei lipase. | steady-state and time-resolved fluorescence-quenching measurements have been performed to study multitryptophan lipase from filamentous fungus rhizomucor miehei. using the steady-state acrylamide fluorescence quenching data and the fluorescence-quenching-resolved-spectra (fqrs) method, the total emission spectrum of native ("closed-lid") lipase has been decomposed into two distinct spectral components accessible to acrylamide. according to fqrs analysis, more quenchable component has a maximum o ... | 2005 | 15963433 |
| bioreactors based on immobilized cells. | for purification of oil-containing sewage water of oil-proceeding enterprises it has been elaborated by authors the laboratory bioreactor on the basis of immobilized mycelial mucor miehei fungus cells with periodical and constant supply of purified solution. the purification process is tested on model and real oil-containing liquid wastes. it has been established that under true bioreactor exploitation, 1 g of mucor miehei immobilized cells enables to purify more than 100 l of sewage water, cont ... | 2001 | 15954606 |
| chemical and physical properties of butterfat-vegetable oil blend spread prepared with enzymatically transesterified canola oil and caprylic acid. | structured lipid was synthesized from canola oil and caprylic acid with sn-1,3 specific lipase from rhizomucor miehei. cold spreadable butter was made by blending butterfat with the sl at a weight ratio of 80:20. its chemical and physical properties were compared with pure butter and butterfat-canola oil 80:20 blend spread. the butterfat-sl blend had lower contents of hypercholesterolemic fatty acids (fas) and the lowest atherogenic index (ai) as compared to the others. melting and crystallizati ... | 2005 | 15941341 |
| a new sunscreen of the cinnamate class: synthesis and enzymatic hydrolysis evaluation of glyceryl esters of p-methoxycinnamic acid. | glyceryl esters of p-methoxycinnamic acid, 1,3-dipalmitoyl-2-p-methoxycinnamoyl-1,2,3-propanetriol and 1,3-dioctanoyl-2-p-methoxycinnamoyl-1,2,3-propanetriol were synthesised in an attempt to increase substantivity and decrease eventual undesirable effects of sunscreens of this class. to assess if the glyceryl esters could present a higher stability towards hydrolysis by lipases in the stratum corneum, hydrolysis rates were determined in vitro using a commercial fungal lipase from rhizomucor mie ... | 2005 | 15854802 |
| preparation of mono- and diacylglycerols by enzymatic esterification of glycerol with conjugated linoleic acid in hexane. | esterification of glycerol with conjugated linoleic acid (cla) was carried out in hexane. lipase from rhizomucor miehei provided a high degree of esterification (80%) in 8 h at 50 degrees c when used at 15% (w/w) in a system containing a 1:2 molar ratio of glycerol to free fatty acids. esterification levels >80% were obtained in 8 h at 40 degrees c with 15% (w/w) lipase from candida antarctica at the same molar ratio of reactants. the extent of esterification of cla was >90% after 4 h of reactio ... | 2005 | 15834163 |
| lipase-catalyzed synthesis of l-phenylalanyl-d-glucose. | regioselective synthesis of l-phenylalanyl ester of d-glucose with unprotected l-phenylalanine and d-glucose was carried out in organic solvents using lipases from rhizomucor miehei (rml) and porcine pancreas (ppl). the reaction was investigated in terms of free unprotected l-phenylalanine, d-glucose, rml and ppl concentrations, buffer salts (ph and concentration), enzyme reusability and incubation period. under the experimental conditions employed, both the enzymes exhibited good esterification ... | 2005 | 15831247 |
| direct separation of regio- and enantiomeric isomers of diacylglycerols by a tandem column high-performance liquid chromatography. | a novel hplc-based method for direct separation of the three isomers of mono-acid diacylglycerols (dags), i.e., 1,2-dag, 2,3-dag and 1,3-dag, has been established. the method employs a tandem column system, in which two different columns (a conventional silica gel column and a chiral stationary phase column) are connected in series. two isomeric mixtures of dags (i.e., dicapryloylglycerol and dioleoylglycerol) and lipase-catalyzed reaction mixtures were successfully resolved on the tandem column ... | 2005 | 15830930 |
| stabilization of enzymes by multipoint immobilization of thiolated proteins on new epoxy-thiol supports. | the controlled and partial modification of epoxy groups of eupergit c and ep-sepabeads with sodium sulfide has permitted the preparation of thiol-epoxy supports. their use allowed not only the specific immobilization of enzymes through their thiol groups via thiol-disulfide interchange, but also enzyme stabilization via multipoint covalent attachment. penicillin g acylase (pga) from escherichia coli and lipase from rhizomucor miehei were used as model enzymes. both enzymes lacked exposed cystein ... | 2005 | 15818562 |
| favolon b, a new triterpenoid isolated from the chilean mycena sp. strain 96180. | a new biologically active triterpenoid, favolon b (1), was isolated from fermentation broths of mycena sp. strain 96180. favolon b showed antifungal activities towards botrytis cinerea, mucor miehei, paecilomyces variotii and penicillium notatum. no activities were observed against bacteria and yeasts. the structure of favolon b was elucidated by spectroscopic techniques. | 2005 | 15813182 |
| mutational analysis of a feruloyl esterase from aspergillus awamori involved in substrate discrimination and ph dependence. | we cloned the feruloyl esterase a gene from aspergillus awamori (awfaea) and engineered it to study substrate specificity and ph dependence of catalysis. based on the crystal structures of two type-a feruloyl esterases (fae-iii and anfaea) from aspergillus niger, residues located in the flap region of awfaea (asp71, thr72, asp77, and tyr80) were replaced with corresponding amino acid residues (ile, arg, asn, and phe), respectively, found in the lid of lipases from rhizomucor miehei (rmlip) and h ... | 2005 | 15716038 |
| relative effectiveness of pretreatments on performance of rhizomucor miehei lipase in nonpolar reaction media. | enzymes can be used in nonpolar reaction media to modify water-insoluble substrates. a variety of pretreatments, applied to the enzyme prior to introduction to the nonpolar media, can improve enzyme activity. however, the various pretreatments have not been studied using directly comparable conditions, nor have they been applied simultaneously to test for interactive effects. this work evaluates pretreatment of lipase with various classes of additives. the pretreated lipase is used to catalyze e ... | 2005 | 15695838 |
| enzymatic procedures in the preparation of regioprotected d-fructose derivatives. | a combination of different lipases from pseudomonas cepacia, candida antarctica b, candida rugosa and mucor miehei, aided the regioesterification of the free fructose allowing the synthesis of 1,6-di-o-acetyl-d-fructofuranose, 1,4,6-tri-o-acetyl-d-fructofuranose, 1,6-di-o-acetyl-4-o-benzoyl-d-fructofuranose and 1,6-di-o-benzoyl-d-fructofuranose. using c. antarctica b and c. rugosa lipases the alcoholysis of fructose peracetate (alpha, beta-form) has furnished 1,2,3,4-tetra-o-acetyl-alpha-d-fruct ... | 2005 | 15639253 |
| lipase catalyzed synthesis of l-alanyl, l-leucyl and l-phenylalanyl esters of d-glucose using unprotected amino acids. | enzymatic synthesis of l-alanyl, l-leucyl and l-phenylalanyl esters of d-glucose was carried out in a non-polar solvent using lipases from rhizomucor miehei and porcine pancreas. the unprotected amino acids at millimolar concentrations were used in presence of 10 to 50% (w/w) glucose of the lipases to give ester yields up to >99%. the reaction mixture on analysis by 2-d nmr showed that the product is a mixture of 6-o-, 3-o- and 2-o-monoesters and 2,6-di-o- and 3,6- di-o-esters. | 2004 | 15604758 |
| differentiation of rhizomucor species on the basis of their different sensitivities to lovastatin. | the opportunistic pathogens rhizomucor pusillus and rhizomucor miehei may be agents of frequently fatal mycotic diseases. in the present study, the susceptibilities of 27 clinical and environmental isolates of r. miehei and r. pusillus to lovastatin under different culturing conditions were investigated. most of the r. miehei strains grew at lovastatin concentrations as high as 64 to 128 microg/ml. in contrast, the inhibitory effect of lovastatin on all of the r. pusillus strains was evident at ... | 2004 | 15528755 |
| biocatalyzed acidolysis of soybean oil triacylglycerols to increase oleic acid content. | lipase catalyzed acidolysis of triacylglycerols (tag) of soybean oil with oleic acid in organic solvent was studied; immobilized lipase from rhizomucor miehei was used and the effects of reaction time, incubation temperature and enzyme load on tag total and positional fatty acid (fa) percentage compositions were investigated. the results show that oleic acid incorporation was high after 24 and 48 h, while after 72 h a lower level of oleic acid in tag was observed. moreover, for the reactions car ... | 2004 | 15527134 |
| immobilization of rennet from mucor miehei via its sugar chain. its use in milk coagulation. | a successful strategy for the immobilization of rennet from mucor miehei has been developed. the strategy is based on the immobilization of the enzyme, via their sugar chains at high ionic strength on aminated supports having primary amino groups with a very low pk value. the rennet was covalently immobilized via sugar chains (previously oxidized with periodate), which act as natural spacer arms and allow a very high percentage of rennet activity to be kept against small (h-leu-ser-p-nitro-phe-n ... | 2004 | 15360320 |
| cloning and characterization of the acid lipase from castor beans. | castor bean endosperm contains a well known acid lipase activity that is associated with the oil body membrane. in order to identify this enzyme, proteomic analysis was performed on purified oil bodies. a approximately 60-kda protein was identified (rcobl1), which shares homology with a lipase from the filamentous fungus rhizomucor miehei. rcobl1 contains features that are characteristic of an alpha/beta-hydrolase, such as a putative catalytic triad (sdh) and a conserved pentapeptide (gxsxg) sur ... | 2004 | 15322116 |
| solvent-free lipase-catalyzed preparation of diacylglycerols. | various methods have been applied for the enzymatic preparation of diacylglycerols that are used as dietary oils for weight reduction in obesity and related disorders. interesterification of rapeseed oil triacylglycerols with commercial preparations of monoacylglycerols, such as monomuls 90-o18, mulgaprime 90, and nutrisoft 55, catalyzed by immobilized lipase from rhizomucor miehei (lipozyme rm im) in vacuo at 60 degrees c led to extensive (from 60 to 75%) formation of diacylglycerols. esterific ... | 2004 | 15315368 |
| a kinetic study on lipase-catalyzed interesterification of soybean oil with oleic acid in a continuous packed-bed reactor. | to provide a mathematical basis for the design and operation of a continuous, packed-bed reactor for the interesterification of soybean oil, soybean oil that contains 22.7% oleoyl and 54.3% linoleoyl moieties as molar acyl moiety composition was interesterified in hexane with oleic acid, using an immobilized sn-1,3-specific lipase (lipozyme im) from mucor miehei. the reaction was carried out in a u-shaped pyrex glass-made packed-bed reactor at 37 degrees c in the following system: concentration ... | 1999 | 15304780 |
| lipase-catalyzed production of short-chain acids terpenyl esters of interest to the food industry. | the production of low molecular weight esters as flavor compounds by biotechnological processes has a potential interest for the food industry. the use of natural available substrates and enzymes is an essential part of the process design, because the products may obtain natural label. in this study, direct esterification of citronellol and geraniol with short-chain fatty acids catalyzed by free lipase from mucor miehei was performed with high yields in n-hexane. the effects of the acid:alcohol ... | 1999 | 15304771 |
| crystallization and preliminary x-ray structure solution of rhizomucor miehei aspartic proteinase. | rhizomucor miehei aspartic proteinase (m(r) = 38701, 361 residues) has been crystallized in a form suitable for analysis by x-ray diffraction. the flattened rod-shaped crystals were grown from polyethylene glycol 8000 using vapour-diffusion methods. the crystal form is in space group p2(1)2()12(1) [a = 41.67 (2), b = 51.21 (3) and c = 173.3 (2) a], with z = 4 and one molecule in the asymmetric unit. data were collected over the range 0 < h < 14, 0 < k < 16 and 0 < l < 62, resulting in 7032 uniqu ... | 1995 | 15299327 |
| reversible and strong immobilization of proteins by ionic exchange on supports coated with sulfate-dextran. | new and strong ionic exchange resins have been prepared by the simple and rapid ionic adsorption of anionic polymers (sulfate-dextran) on porous supports activated with the opposite ionic group (deae/manae). ionic exchange properties of such composites were strongly dependent on the size of the ionic polymers as well as on the conditions of the ionic coating of the solids with the ionic polymers (optimal conditions were 400 mg of sulfate-dextran 5000 kda per gram of support). around 80% of the p ... | 2004 | 15296440 |
| cloning and sequence analysis of the glyceraldehyde-3-phosphate dehydrogenase gene from the zygomycetes fungus rhizomucor miehei. | rhizomucor miehei is important from a biotechnological aspect in consequence of its content of aspartic proteinase, which has high milk-clotting activity. a genomic library of r. miehei nrrl 5901 has been constructed in a phage (lambda fix ii) vector. the glyceraldehyde-3-phosphate dehydrogenase (gpd) gene was isolated from this library by hybridization of the recombinant phage clones with a gpd-specific gene probe generated by polymerase chain reaction. the complete nucleotide sequence encodes ... | 2004 | 15280645 |
| quinazolin-4-one derivatives from streptomyces isolates. | from the ethyl acetate extract of the strain streptomyces sp. isolate gw23/1540, besides 16 known products, several 1h-quinazolin-4-one derivatives were isolated. (sr)-2-(1-hydroxyethyl)-2-methyl-2,3-dihydro-1h-quinazolin-4-one (4) and (rr)-2-(1-hydroxyethyl)-2-methyl-2,3-dihydro-1h-quinazolin-4-one (5) are new natural products. 2-methyl-3h-quinazolin-4-one (2) and 1h-quinazoline-2,4-dione (3) are known from other bacteria and plants, respectively. from another streptomyces sp., gw2/577, 5-methy ... | 2004 | 15270566 |
| controllable regioselective enzymatic synthesis of polymerizable 5'-o-vinyl- and 3'-o-vinyl-nucleoside analogues in acetone. | an efficient synthesis of polymerizable 3'- and 5'-o-acyl-nucleoside derivatives has been developed from inosine and 2'-deoxyuridine by enzyme-catalyzed regioselective acylation with divinyl dicarboxylates. in acetone, lipozyme (immobilized lipase from mucor miehei) gave 5'-o-acyl-nucleoside products, and ppl (lipase from porcine pancreas) provided 3'-o-acyl-nucleoside products. | 2004 | 15269530 |
| use of immobilized lipases for lipase purification via specific lipase-lipase interactions. | lipase from pseudomonas fluorescens (pfl), an enzyme with a great tendency to yield bimolecular aggregates, was immobilized via multipoint covalent attachment on glyoxyl-agarose in the presence of triton x-100. this strategy permitted to obtain the enzyme with the active center oriented towards the reaction medium. this immobilized enzyme presents the capacity of specifically adsorbing pfl molecules, that can be easily desorbed by the use of detergents. more interesting, the enzyme was also able ... | 2004 | 15233541 |
| a novel hydrophilic support, cofoam, for enzyme immobilization. | lipases from different sources (porcine pancreas, mucor miehei and candida antarctica b) were covalently immobilized on a hydrophilic polyurethane composite (cofoam). their hydrolytic activities assayed with tributyrin were 0.55, 2.1 and 447 u g(-1), respectively. the activity of the c. antarctica b composite in the synthesis of methyl oleate in hexane was 8.8 u g(-1) compared to 60.6 u g(-1) for commercial novozyme 435. the advantage of the cofoam composite lies in the low pressure drop in a pa ... | 2004 | 15127787 |
| ester synthesis catalyzed by mucor miehei lipase immobilized on magnetic polysiloxane-polyvinyl alcohol particles. | mucor miehei lipase was immobilized on magnetic polysiloxane-polyvinyl alcohol particles by covalent binding with high activity recovered. the performance of the resulting immobilized biocatalyst was evaluated in the synthesis of flavor esters using heptane as solvent. the impact on reaction rate was determined for enzyme concentration, molar ratio of the reactants, carbon chain length of the reactants, and alcohol structure. ester synthesis was maximized for substrates containing excess acyl do ... | 2004 | 15054206 |
| mono-thioesters and di-thioesters by lipase-catalyzed reactions of alpha,omega-alkanedithiols with palmitic acid or its methyl ester. | 1- s-mono-palmitoyl-hexanedithiol and 1- s-mono-palmitoyl-octanedithiol were prepared in high yield (80-90%) by solvent-free lipase-catalyzed thioesterification of palmitic acid with the corresponding alpha,omega-alkanedithiols in vacuo. similarly, 1,6-di- s-palmitoyl-hexanedithiol and 1,8-di- s-palmitoyl-octanedithiol were prepared in moderate yield (50-60%) by solvent-free lipase-catalyzed thioesterification of palmitic acid with 1- s-mono-palmitoyl-hexanedithiol and 1- s-mono-palmitoyl-octane ... | 2004 | 15048592 |
| evidence for selective hydrolysis of aliphatic copolyesters induced by lipase catalysis. | high molar mass random poly(butylene succinate-co-butylene sebacate), p(bs-co-bse), and poly(butylene succinate-co-butylene adipate), p(bs-co-ba), with different composition, were synthesized and subjected to enzymatic hydrolysis by lipase from mucor miehei or from rhizopus arrhizus. the enzymatic hydrolysis of p(bs-co-bse)s and p(bs-co-ba)s films produced a mixture of water-soluble monomers and co-oligomers that were separated and identified by on-line high performance liquid chromatography/ele ... | 2004 | 15003003 |
| hyperactivation of rhizomucor miehei lipase by hydrophobic xerogels. | although a variety of approaches exist for the immobilization of enzymes, the "science" of enzyme immobilization is still in its infancy. in recent years, considerable interest has developed regarding the use of xerogels for enzyme immobilization. there are several advantages to xerogels for enzyme immobilization, including the opportunity to produce them in defined shapes or thin films and the ability to manipulate their physical characteristics (e.g., porosity, hydrophobicity, and optical prop ... | 2004 | 14966806 |
| lipase-catalyzed methanolysis of triricinolein in organic solvent to produce 1,2(2,3)-diricinolein. | the objective of this study was to find the optimal parameters for lipase-catalyzed methanolysis of triricinolein to produce 1,2(2,3)-diricinolein. four different immobilized lipases were tested, candida antarctica type b (calb), rhizomucor miehei (rml), pseudomonas cepacia (pcl), and penicillium roquefortii (prl). n-hexane and diisopropyl ether (dipe) were examined as reaction media at three different water activities (a(w)), 0.11, 0.53, and 0.97. the consumption of triricinolein and the format ... | 2003 | 14733366 |
| phylogenetic relationship of the genus gilbertella and related genera within the order mucorales based on 5.8 s ribosomal dna sequences. | the complete its (internal transcribed spacer) region coding the its1, the its2 and the 5.8s rdna was amplified by polymerase chain reaction from two strains of gilbertella persicaria, six strains in the mucoraceae (mucor piriformis, m. rouxii, m. circinelloides, rhizomucor miehei, r. pusillus and r. tauricus) and four strains representing three species of the choanephoraceae (blakeslea trispora, choanephora infundibulifera and poitrasia circinans). sequences of the amplified dna fragments were ... | 2003 | 14711043 |
| enzymatic synthesis of phosphocarnitine, phosphogabob and fosfomycin. | phosphocarnitine was conveniently obtained from easily available diethyl 3-chloro-2-oxopropanephosphonates, followed by subsequent reduction, mucor miehei lipase (im) mediated resolution, amination and dealkylation. candida antarctica lipase b (calb) served as an effective biocatalyst in the resolution of several 1- or 2-hydroxyalkanephosphonates. the chlorine atom in different positions on the molecules greatly affected their enantioselectivity. calb also showed satisfactory enantioselectivity ... | 2003 | 14599018 |
| [rennet production by rhizomucor miehei nrrl 3169]. | the production of rennet was studied, using different strains of the fungus rhizomucor miehei. the selection and preservation of strains, type of growth, media design and operation conditions were evaluated. the experiments were carried out in erlenmeyer flasks in rotary shaker at 250 rpm and 2.5 eccentricity, and in mechanically stirred fermentors of the new brunswick type, at 30 degrees c. in the studies concerning strain selection, the best strain was rhizomucor miehei nrrl 3169. the major ti ... | 2003 | 14587373 |
| downstream processing of microbial rennet from solid state fermented moldy bran. | in recent years due to acute shortage of calf-rennet, microbial rennets seem to be an effective alternative and are commercially produced. mucor miehei was cultivated under the solid state fermentation conditions, and the moldy bran was extracted using a semicontinuous multiple contact forced percolation method. the treated extract was then filtered through 5% r16 clay which enabled easy and efficient removal of impurities such as lipase and protease without involving costly chemical treatments. ... | 1993 | 14545664 |
| polar organic solvent added to an aqueous solution changes hydrolytic property of lipase. | for developing further uses of lipase as a biocatalyst, its hydrolytic activity toward some esters was investigated in a miscible solution composed of a buffer and a polar organic solvent. twenty percent dimethylformamide, 35% dimethylsulfoxide, 15% 1,4-dioxane, 15% dimethoxyethane, and 2% diethoxyethane promoted the hydrolysis by a lipase from rhizomucor miehei toward some hydrophobic substrates, 4-methylumbelliferyl oleate, 4-methylumbelliferyl palmitate, and monoolein. while hydrolysis by thi ... | 2003 | 12951497 |
| transformation of mucor miehei results in plasmid deletion and phenotypic instability. | mucor miehei transformants resistant to geneticin have been obtained by treatment of protoplasts with different plasmids and by agrobacterium-mediated dna transfer. all transformants exhibited a very unstable phenotype whose maintenance required continuous selective pressure. molecular analysis of transformants showed that the plasmid dna was extensively modified and maintained in very low amount. our results indicate that m. miehei reluctance to transformation is due to different causes, includ ... | 2003 | 12855175 |
| cloning of an alkaline lipase gene from penicillium cyclopium and its expression in escherichia coli. | the gene encoding an alkaline lipase of penicillium cyclopium pg37 was cloned with four steps of pcr amplification based on different principles. the cloned gene was 1,480 nucleotides in length, consisted of 94 bp of promoter region, and had 6 exons and 5 short introns ranging from 50 to 70 nucleotides. the open reading frame encoded a protein of 285 amino acid residues consisting of a 27-aa signal peptide and a 258-aa mature peptide, with a conserved motif of gly-x-ser-x-gly shared by all types ... | 2003 | 12784858 |
| synthesis of ethyl isovalerate using rhizomucor miehei lipase: optimization. | immobilized lipase from rhizomucor miehei (lipozyme im-20) was used to catalyze the esterification reaction between isovaleric acid and ethanol to synthesize ethyl isovalerate in n-hexane. response surface methodology based on five-level four-variable central composite rotatable design was employed to optimize four important reaction variables such as enzyme/substrate e/s ratio, substrate concentration, incubation time, and temperature affecting the synthesis of ethyl isovalerate. the optimum co ... | 2003 | 12754824 |
| lipase-mediated deacetylation and oligomerization of lactonic sophorolipids. | the direct enzymatic polymerization of lactonic sophorolipids (sls) was investigated with four lipases, including porcine pancreatic lipase (ppl), immobilized mucor miehei lipase (mml), lyophilized candida antarctica lipase (fraction b, cal-b), and lyophilized pseudomonas sp. lipase (psl). several organic solvents, covering a wide range of polarity, were compared for suitability as the reaction medium. isopropyl ether and toluene were found most effective. according to the quantification and str ... | 2003 | 12675564 |
| [synthesis of partial glycerol caprates by using lipase in nonaqueous media]. | enzymatic esterification by reacting caparic acid with glycerol in solvent-free system was studied. lipases from pseudomonas fluoresces(pfl), mucor miehei(mml) and candida antarictica(cal) possessed good catalytic activity. the optimal reaction conditions to convert capric acid with cal are: 60 degrees c, 20-100 u of cal per gram capric acid, 12% (w/w) of initial water content in glycerol. cal does not express its 1,3-specificity in final product. mechanical fraying denatured cal partly. 96.4% o ... | 2002 | 12674646 |
| effects of temperature and pressure on rhizomucor miehei lipase stability. | both high temperature and high hydrostatic pressure induce irreversible deactivation of enzymes. they enable the enzyme's thermodynamic parameters to be determined and are used to study the mechanisms involved in biochemical systems. the effect of these two factors on the stability of rhizomucor miehei lipase have been investigated. the stability criterion used was residual hydrolytic activity of the lipase. experimental and theoretical parameters, obtained by linear regression analysis, were co ... | 2003 | 12668311 |
| lipase-catalyzed interesterification of soybean oil with an omega-3 polyunsaturated fatty acid concentrate prepared from sardine oil. | to reduce the content of linoleoyl moiety in soybean oil, soybean oil that contains 53.0% linoleoyl moiety as molar acyl moiety composition was interesterified with an omega-3 polyunsaturated fatty acid (pufa) concentrate (24.0 mol% eicosapentaenoic acid [epa], 40.4 mol% docosahexaenoic acid [dha]) prepared from sardine oil, using an immobilized sn-1,3-specific lipase from rhizomucor miehei (lipozyme im). the reaction was carried out in a batch reactor at 37 degrees c under the following conditi ... | 2003 | 12603099 |
| effect of polar head groups on the activity of aspartyl protease adsorbed to lipid membranes. | the proteolytic activity of an aspartyl protease of mucor miehei was correlated with the adsorption of the protease to lipid vesicles. it was observed that the presence of phosphatidylethanolamines (pe's) in the membrane increased the enzyme activity in a 20% in the gel phase and 10% in the fluid phase. the effects of protease on the surface pressure of monolayers composed by dioleoylphosphatidylcholine (dopc), dimyristoylphosphatidylcholine (dmpc), dimyristoyl phosphatidylethanolamine (dmpe) we ... | 2003 | 12598050 |
| optimization of lipase-catalyzed biodiesel by response surface methodology. | biodiesel prepared by catalyzed mild transesterification has become of much current interest for bioenergy. the ability of a commercial immobilized lipase (novo industries--bagsvaerd, denmark) from rhizomucor miehei (lipozyme im-77) to catalyze the transesterification of soybean oil and methanol was investigated in this study. response surface methodology and 5-level-5-factor central composite rotatable design were employed to evaluate the effects on reaction time, temperature, enzyme amount, mo ... | 2003 | 12576002 |
| general trend of lipase to self-assemble giving bimolecular aggregates greatly modifies the enzyme functionality. | three microbial lipases (those from candida rugosa, humicola lanuginosa, and mucor miehei) have been found to exhibit a tendency to form bimolecular aggregates in solution even at very low enzyme concentrations (44 microg/ml) in the absence of a detergent, as detected by gel filtration. the monomolecular form of the enzymes was found as unique only at low enzyme concentration and in the presence of detergents. however, in the case of the lipase b from candida antarctica, no bimolecular form coul ... | 2003 | 12523838 |
| pharacine, a natural p-cyclophane and other indole derivatives from cytophaga sp. strain am13.1. | from the ethyl acetate extract of the bacterial strain cytophaga sp. am13.1, among many known compounds, the new natural products 2,5-bis(3-indolylmethyl)pyrazine (2) and a highly symmetrical p-cyclophane named pharacine (5) were identified. in addition, tryptamine isovalerate (1) and p-hydroxyphenylacetamide (4), known as plant metabolites, were isolated and characterized from a microorganism for the first time. the new natural products showed no activity against three microalgae, the fungus mu ... | 2002 | 12444694 |
| phytotoxic arylethylamides from limnic bacteria using a screening with microalgae. | n-phenylethylamides 1a-1f, were isolated from cultures of three limnic strains gw90a, gw102a and gw73a. strain gw102a delivered additionally the compound cyclo(isoleucyldehydroalanyl) (2). the structure of these compounds were assigned by a detailed spectral analysis. due to their potential use as herbicides, various related compounds 1a, 3, 4a and 4b were synthesized. the minimum inhibitory concentration (mic) against chlorella vulgaris, chlorella sorokiniana, chlorella salina and scenedesmus s ... | 2002 | 12243454 |
| enantiomeric resolution of 2-aryl propionic esters with hyperthermophilic and mesophilic esterases: contrasting thermodynamic mechanisms. | the enantiomeric resolution of 2-aryl propionic esters by hyperthermophilic and mesophilic esterases was found to be governed by contrasting thermodynamic mechanisms. entropic contributions predominated for mesophilic esterases from candida rugosa and rhizomucor miehei, while enthalpic forces controlled this resolution by the esterase from the extremely thermoacidophilic archaeon, sulfolobus solfataricus p1. this disparity in thermodynamic mechanism can be attributed to the differences in confor ... | 2002 | 12105890 |
| enzymatic esterification of an acid with an epoxide using an immobilized lipase from mucor miehei as catalyst: optimization of the yield and isomeric excess of ester by statistical analysis. | we have developed the methodology for the esterification of an acid with an epoxide using 2-chlorobutyric acid and 1,2-epoxy-5-hexene catalysed by a mucor miehei-immobilized lipase. thus, this methodology could be applied to obtain 2-chloroesters. a factorial design of experiments and a central composite design have been used to optimise the synthesis of these esters. the variables chosen were temperature and initial catalyst concentration, while the responses were yield and isomeric excess of t ... | 2002 | 12074092 |
| microwave-assisted rapid characterization of lipase selectivities. | a rapid screening procedure for characterization of lipase selectivities using microwaves was developed. the rate of reaction of various commercial lipases (porcine pancreas, mucor miehei, candida rugosa, pseudomonas cepacia) as well as lipases from laboratory isolates-bacillus stearothermophilus and burkholderia cepacia rgp-10 for triolein hydrolysis was 7- to 12-fold higher in a microwave oven as compared to that by ph stat. the esterification of sucrose/methanol and ascorbic acid with differe ... | 2002 | 12062110 |
| effective enzymatic resolution of rac-1-(3-trifluoromethylphenyl)propan-2-ol, precursor of fenfluramine. | lipases from candida antarctica and from mucor miehei efficiently catalyze the enantioselective esterification of rac-1-(3-trifluoromethylphenyl)propan-2-ol. the obtained enantioforms are suitable to prepare both enantiomers of fenfluramine. | 2002 | 11968073 |
| 5-[4-(1-hydroxyethyl)phenyl]-10,15,20-triphenylporphyrin as a probe of the transition-state conformation in hydrolase-catalyzed enantioselective transesterifications. | 5-[4-(1-hydroxyethyl)phenyl]-10,15,20-triphenylporphyrin (1a) and zinc porphyrin 1b were designed and synthesized to experimentally examine the validity of the transition-state model previously proposed for the lipase-catalyzed kinetic resolution of secondary alcohols. the lipases from pseudomonas cepacia (lipase ps), candida antarctica (chirazyme l-2), rhizomucor miehei (chirazyme l-9), and pseudomonas aeruginosa (lipase lip) exhibited excellent enantioselectivity (e >100 at 30 degrees c). subt ... | 2002 | 11925221 |
| lipase-catalysed hydrolysis of short-chain substrates in solution and in emulsion: a kinetic study. | we have studied the enzymatic hydrolysis of solutions and emulsions of vinyl propionate, vinyl butyrate and tripropionin by lipases of various origin and specificity. kinetic studies of the hydrolysis of short-chain substrates by microbial triacylglycerol lipases from rhizopus oryzae, mucor miehei, candida rugosa, candida antarctica a and by (phospho)lipase from guinea-pig pancreas show that these lipolytic enzymes follow the michaelis-menten model. surprisingly, the activity against solutions o ... | 2001 | 11750885 |
| synthesis of structured triacylglycerols containing caproic acid by lipase-catalyzed acidolysis: optimization by response surface methodology. | production in a batch reactor with a solvent-free system of structured triacylglycerols containing short-chain fatty acids by lipozyme rm im-catalyzed acidolysis between rapeseed oil and caproic acid was optimized using response surface methodology (rsm). reaction time (t(r)), substrate ratio (s(r)), enzyme load (e(l), based on substrate), water content (w(c), based on enzyme), and reaction temperature (t(e)), the five most important parameters for the reaction, were chosen for the optimization. ... | 2001 | 11743762 |
| steryl and stanyl esters of fatty acids by solvent-free esterification and transesterification in vacuo using lipases from rhizomucor miehei, candida antarctica, and carica papaya. | sitostanol has been converted in high to near-quantitative extent to the corresponding long-chain acyl esters via esterification with oleic acid or transesterification with methyl oleate or trioleoylglycerol using immobilized lipases from rhizomucor miehei (lipozyme im) and candida antarctica (lipase b, novozym 435) as biocatalysts in vacuo (20-40 mbar) at 80 degrees c, whereas the conversion was markedly lower at 60 and 40 degrees c. corresponding conversions observed with papaya (carica papaya ... | 2001 | 11714305 |
| dynamics of the substrate binding pocket in the presence of an inhibitor covalently attached to a fungal lipase. | to gain insight into the mobility of the occupied ligand-binding pocket of the rhizomucor miehei lipase we have conducted a rigorous molecular dynamics analysis. the covalently attached inhibitor, ethylhexylphosphonate, was employed as a mimic of the putative tetrahedral intermediate in the esterolytic reaction. our results show that in this lipase, ligand recognition is influenced by the flexibility of the binding pocket, a feature that is common to many other enzymes. several regions around th ... | 2001 | 11565841 |
| effect of water activity and immobilization on fatty acid selectivity for esterification reactions mediated by lipases. | the effect of water activity (a(w)) and immobilization on fatty acid (fa) selectivity of burkholderia (formerly pseudomonas) cepacia, rhizomucor miehei, candida antarctica (type b), and candida rugosa lipases in esterification reactions was determined. studies were based on measuring ester formation in multicompetitive reaction mixtures containing either the homologous series of even carbon number n-chain saturated fa (c4-c18) or a series of n-chain (un)saturated fa (c18:x, where x = 0-3 double ... | 2001 | 11536145 |
| tuning lipase enantioselectivity in organic media using solid-state buffers. | the enantioselectivity exhibited by candida antarctica lipase b (calb) in predominantly organic media has been studied for different enzyme protonation states. alcoholysis of (+/-)-2-phenyl-4-benzyloxazol-5(4h)-one (1) using butan-1-ol as the nucleophile in low-water organic solvents was used as a model reaction. using either organo-soluble bases or the newly introduced solid-state buffers of known pk(a), the protonation state of the lipase was altered. by choice of the appropriate solid-state b ... | 2001 | 11463259 |
| study of lipase-catalyzed hydrolysis of some monoterpene esters. | studies of the hydrolysis of bornyl, citronellyl, geranyl, and terpenyl acetates by commercially available lipases of candida rugosa, rhizopus arrhizus, and mucor miehei are presented. the hydrolysis of these monoterpene esters is investigated at various temperatures and phs, and the time dependence of the percentage of esters hydrolysed is studied. the catalytic activities of the lipases in hydrolysing the esters are compared and, overall, it is observed that under the experimental conditions u ... | 2001 | 11400729 |
| phage display combinatorial libraries of short peptides: ligand selection for protein purification. | a library of heptapeptides displayed on the surface of filamentous phage m13 was evaluated as a potential source of affinity ligands for the purification of rhizomucor miehei lipase. two independent selection (biopanning) protocols were employed: the enzyme was either physically adsorbed on polystyrene or chemically immobilized on small magnetic beads. from screening with the polystyrene-adsorbed lipase it was found that there was a rapid enrichment of the library with "doublet" clones i.e. the ... | 2001 | 11397457 |
| enantioselectivity of recombinant rhizomucor miehei lipase in the ring opening of oxazolin-5(4h)-ones. | enantioselectivity of enzyme catalysis is often rationalized via active site models. these models are constructed on the basis of comparing the enantiomeric excess of product observed in a series of reactions which are conducted with a range of homologous substrates, typically carrying various side chain substitutions. surprisingly the practical application of these simple but informative 'pocket size' models has been rarely tested in genetic engineering experiments. in this paper we report the ... | 2001 | 11391019 |
| cloning and expression analysis of nhl1, a gene encoding an extracellular lipase from the fungal pea pathogen nectria haematococca mp vi (fusarium solani f. sp. pisi) that is expressed in planta. | the filamentous fungus nectria haematococca (anamorph fusarium solani f. sp. pisi) resides in soil, and attacks pea seedlings in the area of the underground epicotyl and upper tap root, causing foot rot disease. we detected lipase activity during in vitro growth of n. haematococca. subsequently, a lipase gene was cloned and functionally characterised by heterologous expression in saccharomyces cerevisiae. the full-length cdna of 1152 bp was cloned using a 3' race-pcr approach coupled with cdna l ... | 2001 | 11361331 |
| alteration of lipase chain length specificity in the hydrolysis of esters by random mutagenesis. | the feasibility of altering the chain length specificity of industrially important rhizomucor miehei lipase was investigated by randomly mutating phe94 in the protein groove which is responsible for accommodating the acyl chain of the substrate. the recombinant lipase was initially expressed in e. coli. individual colonies were selected, grown, and the dna sequence of the lipase gene determined. fourteen of the 19 possible mutants were identified and each of these was transformed into pichia pas ... | 2001 | 11344447 |
| enzymatic synthesis of isoamyl acetate using immobilized lipase from rhizomucor miehei. | the effects of important reaction parameters for enhancing isoamyl acetate formation through lipase-catalyzed esterification of isoamyl alcohol were investigated in this study. increase in substrate (acid) concentration led to decrease in conversions. a critical enzyme concentration of 3 g l(-1) was detected for a substrate concentration of 0.06 m (each of alcohol and acid). solvents with partition coefficient higher than 1000 (log p>3.0) supported enzyme activity to give high conversions. aceti ... | 2001 | 11334663 |
| replacements of amino acid residues at subsites and their effects on the catalytic properties of rhizomucor pusillus pepsin, an aspartic proteinase from rhizomucor pusillus. | site-directed mutagenesis was carried out to investigate the functional roles of amino acid residues of rhizomucor pusillus pepsin (rmpp) in substrate-binding and catalysis. mutations of two amino acid residues, e13 in the s3 subsite and n219 in the s3/s4 subsites, caused marked changes in kinetic parameters for two substrate peptides with different sequences. further site-directed mutagenesis at e13 suggested that e13 plays a critical role in forming the correct hydrogen bond network around the ... | 2001 | 11328603 |
| optimized synthesis of lipase-catalyzed hexyl acetate in n-hexane by response surface methodology. | hexyl acetate, a short-chain ester with fruity odor, is a significant green note flavor compound and widely used in the food industry. the ability for immobilized lipase from mucor miehei (lipozyme im-77) to catalyze the transesterification of hexanol with triacetin was investigated in this study. response surface methodology and five-level-five-factor central composite rotatable design were adopted to evaluate the effects of synthesis variables, such as reaction time (2-10 h), temperature (25-6 ... | 2001 | 11312836 |
| lipase catalyzed synthesis of organic acid esters of lactic acid in non-aqueous media. | lipases from rhizomucor miehei (lipozyme im20) and porcine pancreas (ppl) were employed as catalysts for the esterification reaction between the hydroxyl group of lactic acid and the carboxyl group of organic acids. reactions were carried out at both shake-flask and bench-scale levels. various parameters, such as solvent, temperature, substrate and enzyme concentrations, effect of buffer volume, buffer ph and water volume, were investigated for optimization of yields. while ethylmethyl ketone (e ... | 2001 | 11278035 |
| optical resolution of asymmetric triacylglycerols by chiral-phase high-performance liquid chromatography. | a simple method for direct optical resolution of some asymmetric triacylglycerols (tgs) has been established. the method employs chiral-phase high-performance liquid chromatography (hplc). an enantiomeric pair of tgs comprising 1-eicosapentaenoyl-2,3-dicapryroyl-sn-glycerol (ecc) and 1,2-dicapryroyl-3-eicosapentaenoyl-sn-glycerol (cce) was resolved on a chiralcel of or on a chiralcel od column. the separation of another pair of asymmetric tgs, 1-docosahexaenoyl-2,3-dicapryroyl-sn-glycerol (dcc) ... | 2001 | 11206777 |
| papaya (carica papaya) lipase with some distinct acyl and alkyl specificities as compared with microbial lipases. | lipase from papaya (carica papaya) latex (cpl), candida antarctica lipase b (novozym 435, nov) and rhizomucor miehei lipase (lipozyme im 20, lip) were used as biocatalysts for the esterification of caprylic acid with straight-chain saturated c(4)-c(18) alcohols and unsaturated c(18) alcohols, such as cis-9-octadecenyl (oleyl, c(18:1), n-9), cis-6-octadecenyl (petroselinyl, c(18:1), n-12), cis-9,cis-12-octadecadienyl (linoleyl, c(18:2), n-6), all-cis-9,12,15-octadecatrienyl (alpha-linolenyl, c(18 ... | 2000 | 11171278 |
| development of small-size tubular-flow continuous reactors for the analysis of operational stability of enzymes in low-water systems. | a very small-scale continuous flow reactor has been designed for use with enzymes in organic media, particularly for operational stability studies. it is constructed from fairly inexpensive components, and typically uses 5 mg of catalyst and flow rates of 1 to 5 ml/h, so only small quantities of feedstock need to be handled. the design allows control of the thermodynamic water activity of the feed, and works with temperatures up to at least 80 degrees c. the reactor has been operated with both n ... | 2001 | 11114661 |
| regioselective enzymatic acylations of polyhydroxylated eudesmanes: semisynthesis, theoretical calculations, and biotransformation of cyclic sulfites. | different lipase enzymes have been tested in order to perform regioselective acetylations on the eudesmane tetrol from vulgarin. high yields (95%) of 1,12-diacetoxy derivative (4) were achieved in 1 h with candida antarctica lipase (cal). however, only the 12-acetyl derivative (6) was obtained in similar yield with mucor miehei (mml) or candida cylindracea (ccl) lipases. the enzymatic protection at c-1 and c-12 has been used to form eudesmane cyclic-sulfites between c-6 and c-4 atoms. the r/s-su ... | 2000 | 11101376 |
| the his gap motif in microbial lipases: a determinant of stereoselectivity toward triacylglycerols and analogs. | lipases preferably hydrolyze the sn-1 and sn-3 acyl chain of triacylglycerols and sn-2 substituted analogs. molecular modeling studies of the stereopreference of microbial lipases from rhizopus oryzae, rhizomucor miehei, candida rugosa, and lipase b from candida antarctica toward the hydrolysis of triacylglycerols and analogs revealed that sterical interactions occurring between the sn-2 substituent and the his gap affect substrate geometry, which can be monitored by a single torsion angle. this ... | 2000 | 11099801 |
| synthesis of glycerides containing n-3 fatty acids and conjugated linoleic acid by solvent-free acidolysis of fish oil. | menhaden oil, a rich source of n-3 fatty acids, was interesterified with conjugated linoleic acid (cla) in a reaction medium composed solely of substrates and either free or immobilized commercial lipase preparations. of five lipases tested, an immobilized preparation from mucor miehei provided the fastest rate of incorporation of cla into fish oil acylglycerols; however, and as observed with most of the lipases utilized, a significant proportion of the n-3 fatty acid residues were liberated in ... | 2000 | 11042555 |
| lipase-catalyzed modification of rice bran oil to incorporate capric acid. | capric acid (c10:0) was incorporated into rice bran oil with an immobilized lipase from rhizomucor miehei as the biocatalyst. effects of incubation time, substrate mole ratio, enzyme load, and water addition on mole percent incorporation of c10:0 were studied. transesterification was performed in an organic solvent, hexane, and under solvent-free condition. pancreatic lipase-catalyzed sn-2 positional analysis and tocopherol analysis were performed before and after enzymatic modification. product ... | 2000 | 10995376 |
| intraspecific variation in two species of rhizomucor assessed by random amplified polymorphic dna analysis. | twenty-three rhizomucor isolates were characterized by random amplified polymorphic dna-pcr (rapd-pcr) with 10-bp oligonucleotide primers. these data were used for numerical analyses to obtain information on the intraspecific genetic polymorphism of rhizomucor species. the genetic variability in rhizomucor pusillus and rhizomucor miehei isolates was found to differ; the latter revealed less intraspecific polymorphism. the different levels of genotypic diversity suggest a correlation with the dif ... | 2000 | 10986673 |
| lipase-mediated hydrolysis of blackcurrant oil. | four commercially available lipases, both free and immobilized, were tested for their ability to catalyze hydrolysis of blackcurrant (ribes nigrum) oil using two different approaches. the lipase from mucor miehei was studied free and immobilized in two different ways. the former series of enzymic reactions were performed in tap water at 40 degrees c, but the latter series of enzymic processes were carried out in mixtures of isooctane and phosphate buffer (in a typical 2/1 ratio of the components ... | 2000 | 10978776 |