bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lipase‐catalyzed enrichment of long‐chain polyunsaturated fatty acids
Authors: McNeill Gerald P. , Ackman Robert G. , Moore Stephen R. 
Published: November 2006

AbstractLipase hydrolysis was evaluated as a means of selectively enriching long‐chain ω3 fatty acids in fish oil. Several lipases were screened for their ability to enrich total ω‐3 acids or selectively enrich either docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA). The effect of enzyme concentration, degree of hydrolysis, and fatty acid composition of the feed oil was studied. Because the materials that were enriched in long‐chain ω3 acids were either partial glycerides or free fatty acids, enzymatic reesterification of these materials to triglycerides by lipase catalysis was also investigated. Hydrolysis of fish oil by eitherCandida rugosa orGeotrichum candidum lipases resulted in an increase in the content of total ω3 acids from about 30% in the feed oil to 45% in the partial glycerides. The lipase fromC. rugosa was effective in selectively enriching either DHA or EPA, resulting in a change of either the DHA/EPA ratio or the EPA/DHA ratio from approximately 1:1 to 5:1. Nonselective reesterification of free fatty acids or partial glycerides that contained ω3 fatty acids could be achieved at high efficiency (approximately 95% triglycerides in the product) by using immobilizedRhizomucor miehei lipase with continuous removal of water.
Solvent polarity influences product selectivity of lipase‐mediated esterification reactions in microaqueous media
Authors: Kuo S. ‐J. , Parkin K. L. 
Published: November 2006

AbstractEsterification reactions were evaluated by using lipases fromRhizomucor miehei (Lipozyme IM20) andPseudomonas cepacia (PS‐30) with equimolar levels (1.77 mmol) of undecanoic acid and glycerol or 1,3‐propanediol (1,3‐PD) or 1,2‐propanediol (1,2‐PD) in organic solvents of log P (partition coefficient between 1‐octanol/water) values of (−0.33–4.5. Reaction yields (percentage of esterified undercanoate) with glycerol ranged from 1.4 to 72%, with greatest yields observed in solvents of log P 4.0–4.5 for Lipozyme, whereas the PS‐30 lipase was similarly effective (27–38% yield) over the full range of solvent polarities. For both enzymes, as solvent apolarity increased, so did the extent of acylation of glycerol in the final product mixture. Reaction yields with 1,3‐PD ranged from 8.1 to 64% for Lipozyme and from 18 to 84% for PS‐30 lipase, with greatest yields observed for both enzymes in solvents of log P values in the range 1.2–5.0. For both lipases, the shift to greater solvent apolarity was accompanied by an increased molar ratio of diacylated‐1,3‐PD/monoacylated‐1,3‐PD in the product mixture. Reaction yields with 1,2‐PD ranged from 2.5 to 45% for Lipozyme and from 12 to 52% for PS‐30 lipase, with greatest yields observed in solvents of log P values in the ranges 1.4–1.9 and 1.4–4.5, respectively. The shift to greater solvent apolarity was accompanied by an increased molar ratio of diacylated‐1,2‐PD: monoacylated‐1,2‐PD in the product mixture, except for Lipozyme in the three most apolar solvents (log P of 3.5–4.5) in which there was a general attenuation of activity. These results suggest the existence of a solvent polarity influence on reaction product selectivity in multiproduct reactions, which can be partially explained on the basis of differential solvation and extraction properties of solvents.
Biocatalytical synthesis and monolayer studies of multiple hydroxylated wax esters
Authors: Lokotsch Wolfram , Lang Siegmund , Möbius Dietmar , Wagner Fritz 
Published: November 2006

AbstractThe continuous production of aleuritic acid decyl ester has been investigated with LipozymeTM as biocatalyst in a fixed‐bed reactor. To avoid the limiting effects of mean substrate solubility, the direct synthesis without organic solvents was chosen, whereby a yield of 90% was obtained depending on the residence time. A comparison of different reaction paths to synthesize a centrally dihydroxylated decyl ester indicated a preference for transesterification of the methyl ester. Under external compression, the interfacial behavior of several enzymatically produced hydroxy wax esters was determined with a Langmuir film balance to find a structure/efficiency relationship. Brewster‐angle microscopy allowed direct visualization of a wax ester monolayer at the air/water interface.
Biotransformation of saturated monohydroxyl fatty acids to 2‐tetrahydrofuranyl acetic acid derivatives: Mechanism of formations and the biological activity of 5‐n‐hexyl‐tetrahydrofuran‐2‐acetic acid
Authors: Huang J. ‐K. , Dowd P. F. , Keudell K. C. , Klopfenstein W. E. , Wen L. , Bagby M. O. , Lanser A. C. , Norton R. A. 
Published: November 2006

AbstractTransformation of 12‐hydroxyoctadecanoic acid (12‐HOA) to 5‐n‐hexyl‐tetrahydrofuran‐2‐acetic acid (5‐HTFA) byBacillus lentus NRRL B‐14864 (B‐14864) was carried out in the presence or absence of oligomycin, 2‐bromooctanoic acid (2‐BA), or sodium azide. In addition, several saturated and monounsaturated monohydroxyfatty acids, saturated monooxofatty acids, and monounsaturated fatty acid were used as substrates for transformation reactions by B‐14864 or corynebacterium FUI‐2. Methyl esters of the transformation products were analyzed by gas chromatography and gas chromatography/mass spectroscopy. Various γ‐lactones and tetrahydrofuran fatty acid derivatives were conversion products when saturated monohydroxyfatty acids were used as substrates; the production of 5‐HTFA from 12‐HOA by B‐14864 cells was completely inhibited in the presence of high concentration of oligomycin, 2‐BA, or sodium azide; and fatty acid β‐oxidation metabolic intermediates, 6‐hydroxydodecanoic, 4‐oxododecanoic, and 4‐oxodecanoic acids were products when 12‐HOA, 10‐oxo‐, and 12‐oxooctadecanoic acids were used as substrates. Our results suggest that the production of 5‐HTFA from 12‐HOA by B‐14864 was through the fatty acid β‐oxidation pathway. Three‐day‐old driedfruit beetle pupae were topically treated with 5‐HTFA to test for juvenile hormone activity, and 5‐HTFA was found to possess juvenile hormone‐like activity in pure form but not when it was diluted to 10%.
Glyceride synthesis in a solvent‐free system
Authors: Fureby Anna Millqvist , Adlercreutz Patrick , Mattiasson Bo 
Published: November 2006

AbstractSynthesis of partial glycerides in a solvent‐free system has been investigated with various acyl donors and glycerol as substrates and a 1,3‐specific immobilized lipase to catalyze the reaction. Capric acid was the most efficient acyl donor, compared with ethyl caprate and tricaprin. However, to obtain a high yield of dicaprin and a low amount of tricaprin, ethyl caprate was the acyl donor of choice. The composition of the product mixture was determined by the ratio of ethyl caprate to glycerol; a molar ratio of 3∶1 was optimum for dicaprin synthesis. The water content in glycerol did not influence the final yield of dicaprin, but initial production of capric acid increased with increasing water content. The reaction was found to be controlled entirely by external mass transfer. The yield of diglyceride could be increased from 70 to 90% by lowering the reaction temperature, so that the diglyceride precipitated during the reaction.
Diesel fuel as a solvent for the lipase‐catalyzed alcoholysis of triglycerides and phosphatidylcholine
Authors: Haas Michael J. , Scott Karen M. 
Published: November 2006

AbstractThe abilities of three commercially available lipases—Lipozyme IM 20, Amano PS‐30, and Amano CE—to synthesize fatty acid ethyl esters via the alcoholysis of soy triglycerides (TG) and phosphatidylcholine (PC) in grade No. 2 diesel fuel were investigated. All three enzyme preparations were active in water‐saturated diesel fuel, synthesizing fatty acid esters from both TG and PC. Response surface methodology, based on a Modified Central Composite design, was employed to examine the coordinate effects of lipid, water, and ethanol concentrations on enzyme activities and to identify conditions yielding maximum alcoholysis. For all three enzymes, optimal activities toward TG occurred at added water concentrations of less than 0.3 M. With PC as substrate, optimal enzyme activities occurred at added water concentrations as much as tenfold greater than this, and the amount of water required for maximum activity was proportional to the substrate concentration. For both substrates the enzyme activities were generally reduced as ethanol concentrations rose. The exceptions to this were the Lipozyme‐TG combination, where activity increased with increasing ethanol concentrations, and the PS‐30‐PC combination, where activity was roughly constant across the range of water and ethanol concentrations examined. Hydrolytic activities of the enzymes in aqueous reactions were poor predictors of transesterification activity in organic solvent: the aqueous hydrolytic activities of CE and PS‐30 toward TG were roughly comparable, and 25 to 50 times greater than that of IM 20. However, in the alcoholysis of TG in diesel fuel the order of activities was PS‐30>IM 20>CE. The activities of Lipozyme and CE toward PC were similar to one another, and PS‐30 was considerably less active on this substrate. CE lipase was more active toward PC than toward TG. Lipozyme displayed comparable activity toward the two substrates. PS‐30 was considerably more active on TG than on PC. Degrees of conversion were consistent with the transesterification of only one fatty acid of TG, and slightly greater than one fatty acid for PC. Preliminary studies indicated that for CE and PS‐30, but not for Lipozyme IM 20, the degree of conversion of TG, but not PC, could be significantly increased by the further provision of ethanol. Expansion of this work could lead to a method for the production of simple fatty acid esters, which are suitable as diesel fuels, from multicomponent agricultural materials containing TG and PC.
Selection of surfactant‐modified lipases for interesterification of triglyceride and fatty acid
Authors: Mogi Ken‐ichi , Nakajima Mitsutoshi 
Published: November 2006

AbstractInteresterification of tripalmitin and stearic acid inn‐hexane was investigated with surfactant‐modified lipases. Various kinds of lipases and surfactants were screened for high interesterification activity of the modified lipases. The modified‐lipase hydrophile‐lipophile balance value and fatty acid group of the surfactants. The modified lipase obtained fromRhizopus japonicus with sorbitan monostearate as surfactant had the highest activity in then‐hexane system. The interesterification activity of the selected modified lipase in molten substrates at 75°C without solvents was the same as that in then‐hexane system at 40°C.
Enzymatic esterification of glycerol III. Lipase‐catalyzed synthesis of regioisomerically pure 1,3‐sn‐diacylglycerols and 1 (3)‐rac‐monoacylglycerols derived from unsaturated fatty acids
Authors: Waldinger Claudia , Schneider Manfred 
Published: November 2006

AbstractLipases that display high regioselectivities and broad substrate tolerance were used as catalysts for the efficient esterification of glycerol under the conditions of irreversible acyl transfer. A variety of unsaturated fatty acids, such as oleic, linoleic, erucic, ricinolic, hydroxystearic and coriolic acid, were used for this purpose in the form of their vinyl esters. Suitable biocatalysts were chosen on the basis of systematic screening experiments regarding their regioselectivities (RE) and substrate tolerances. Distinct differences were found and expressed in numerical RE values as a measure for differences of these biocatalysts as being specific, selective, and nonspecific. Based on these experiments, a variety of molecules were synthesized on a preparative scale (>150 mmol) in good yield (ca.85%) and with high regioisomerical purities (>95% RE).
Synchrotron radiation X‐ray diffraction study on phase behavior of PPP‐POP binary mixtures
Authors: Minato A. , Ueno S. , Yano J. , Wang Z. H. , Seto H. , Amemiya Y. , Sato K. 
Published: November 2006

AbstractThe phase behavior of thesn‐1,3‐dipalmitoyl‐2‐oleoylglycerol (PPP‐POP) binary mixture system was studied by powder X‐ray diffraction with synchrotron radiation and by differential scanning calorimetry. The results showed that the immiscible phases were observed in metastable and in the most stable forms. In particular, synchrotron X‐ray diffraction enabled us to reveal the monotectic nature of α as a kinetic phase behavior. The equilibrium phase diagram of the PPP‐POP mixture is divided into two regions. In POP concentration ratios below 40%, solid‐state transformation from α to β was observed, indicating that the α‐β transition of PPP was promoted in the presence of POP. By contrast, the polymorphic transition proceeds from α to β through the occurrence of the intermediate β′ form at POP concentration ratios above 50%.
Supercritical fluid extraction of sunflower seed oil with CO2‐ethanol mixtures
Authors: Cocero María José , Calvo Lourdes 
Published: November 2006

AbstractThe effect of ethanol addition to supercritical carbon dioxide (SC‐CO2), up to 20%, on sunflower seed oil extraction over the range of 150 to 350 bars and 42 to 80°C was studied. A nonrecirculating home‐made bench‐scale system was used as extraction equipment. The oil‐SC‐CO2‐ethanol mixture was reduced to atmospheric pressure in a test tube, where two phases, oil and ethanol, were obtained and ethanol‐saturated CO2 was liberated to the atmosphere. Results show that sunflower oil solubility in SC‐CO2 greatly increases with addition of ethanol as entrainer over the whole range of pressure and temperature conditions. Some phospholipids are co‐extracted at levels directly proportional to the added ethanol. Moreover, a large amount of phospholipids was recovered in the ethanolic phase. Acidity of the extracted oil with ethanol as entrainer was lower than that without alcohol. Part of the free fatty acids was found in the ethanolic phase.
Direct measurement of thermal fat crystal properties for milk‐fat fractionation
Authors: Breitschuh Birgit , Windhab Erich J. 
Published: November 2006

AbstractThe temperature dependency of the solid‐fat content of a fat is important for predicting the consistency of the final product and for process control. Two direct analytical methods for determining the solid‐fat content and the melting characteristics of milk‐fat fractions have been developed. The fractions are analyzed during crystallization, and the results give reproducible information about the thermal behavior of the fractions and the actual crystal amount in the suspensions. The results are obtained within minutes, and no separation of the fractions before the measurement is necessary. New ways of reducing process time are proposed. It is possible to adapt crystallization time to seasonal variations of the initial milk fat and to the required properties of the final product. Partially crystallized milk fat was directly measured in a calorimeter and a pulsed nuclear magnetic resonance spectrometer. The data showed good correlations and even more accurate results than the conventional methods. The calorimetric method makes it possible to detect polymorphic changes and co‐crystallization in the crystals so that the influence of processing parameters, such as energy input, on crystallization behavior can be investigated.
Conifer seed oils: Distribution of Δ5 acids between α and β chains by13C nuclear magnetic resonance spectroscopy
Authors: Gunstone Frank D. , Wolff Robert L. 
Published: November 2006

AbstractNine seed oils from three different conifer families, already examined by gas chromatography and known to contain diene, triene, and tetraene C18 and C20Δ5 acids, have been reexamined by high‐resolution13C nuclear magnetic resonance spectroscopy. The Δ5 acids are apparent only in the α‐chains. This location is independent of chainlength, double‐bond number, and the species considered and is probably a general factor of conifer seed oils. The spectra confirm the presence of oleic, linoleic, α‐linolenic, and of Δ5 acids and give quantitative information about (total) n‐6, n‐3, and Δ5 acids that is in accord with that obtained by gas chromatography.
Characterization of oleoyl‐12‐hydroxylase in castor microsomes using the putative substrate, 1‐acyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine
Authors: Lin Jiann‐Tsyh , McKeon Thomas A. , Goodrich‐Tanrikulu Marta , Stafford Allan E. 
Published: November 2006

AbstractWe have characterized the oleoyl‐12‐hydroxylase in the microsomal fraction of immature castor bean using the putative substrate, 1‐acyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine (2‐oleoyl‐PC). Previous characterizations of this enzyme used oleoyl‐CoA as substrate and relied on the enzyme transferring oleate from oleoyl‐CoA to lysophosphatidylcholine to form 2‐oleoyl‐PC (acyl‐CoA:lysophosphatidylcholine acyltransferase) in addition to oleoyl‐12‐hydroxylase. The present assay system and characterization use 2‐oleoyl‐PC as substrate (oleoyl‐12‐hydroxylase alone). Use of the actual substrate for assay purposes is important for the eventual purification of the oleoyl‐12‐hydroxylase. Ricinoleate (product of oleoyl‐12‐hydroxylase) and linoleate (product of oleoyl‐12‐desaturase) were identified as metabolites of oleate of 2‐oleoyl‐PC by high‐performance liquid chromatography and gas chromatography/mass spectrometry. The activity of oleoyl‐12‐hydroxylase in the microsomal fraction reached a peak about 44 d after anthesis of castor, while the activity of oleoyl‐12‐desaturase reached a peak about 23 d after anthesis. The optimal temperature for the oleoyl‐12‐hydroxylase was about 22.5°C, and the optimal pH was 6.3. Catalase stimulated oleoyl‐12‐hydroxylase while bovine serum albumin and CoA did not activate oleoyl‐12‐hydroxylase. The phosphatidylcholine analogue, oleoyloxyethyl phosphocholine, inhibited the activity of oleoyl‐12‐hydroxylase. These results further support the hypothesis that the actual subtrate of oleoyl‐12‐hydroxylase is 2‐oleoyl‐PC.
Effects of β‐lactam antibiotics on intestinal microflora and bile acid metabolism in rats
Authors: Hashimoto Shigeru , Igimi Hirotsune , Uchida Kiyohisa , Satoh Takashi , Benno Yoshimi , Takeuchi Nozomu 
Published: November 2006

AbstractWistar male rats were treated for six days with broad spectrum β‐lactam antibiotics, latamoxef, and cefotaxime. On the seventh day, the number of fecal anaerobic microbes decreased, total fecal bile acids decreased, and bile acid pools increased. Secondary bile acids such as β‐hyocholic, hyodeoxycholic, lithocholic, and deoxycholic acids decreased in the feces while the primary bile acids, cholic, β‐muricholic, and chenodeoxycholic acids, became predominant. Coprostanol, a microbial metabolite of cholesterol, also disappeared from the feces during the treatment. The cecum enlarged to almost twice the size of that in control rats, whereas the liver weight was not significantly changed. After treatment was stopped, the number of fecal microbes returned to the initial counts within a week, but restoration of bile acid and cholesterol metabolism required at least three weeks.
Blood lipid docosahexaenoic and arachidonic acid in term gestation infants fed formulas with high docosahexaenoic acid, low eicosapentaenoic acid fish oil
Authors: Innis Sheila M. , Auestad Nancy , Siegman Joel S. 
Published: November 2006

AbstractThe effect of fish oil high in docosahexaenoic acid (22∶6n−3) and low in eicosapentaenoic acid (20∶5n−3) in formula on blood lipids and growth of full‐term infants was studied. Infants were fed formula with about 15% oleic acid (18∶1), 32% linoleic acid (18∶2n−6), 4.9% linolenic acid (18∶3n−3) and 0, 0.10 or 0.22% 22∶6n−3, or 35% 18∶1, 20% 18∶2n−6, 2.1% 18∶3n−3 and 0, 0.11 or 0.24% 22∶6n−3 from 3 d to 16 wk of age (n=16, 18, 17, 21, 17, 16, respectively). The formulae had <0.1% 20∶5n−3 and no arachidonic acid (20∶4n−6). Breast‐fed infants (n=26) were also studied. Plasma phospholipid and red blood cell (RBC) phosphatidylcholine (PC) and phosphatidylethanolamine (PE) fatty acids were determined at 3 d and 4, 8, and 16 wk of age. These longitudinal analyses showed differences in blood lipid 22∶6n−3 between breast‐fed and formula‐fed infants depending on the feeding duration. At 16 wk, infants fed formula with 0.10, 0.11% 22∶6n−3, or 0.22% 22∶6n−3 had similar 22∶6n−3 levels in the plasma phospholipid and RBC PC and PE compared with breast‐fed infants and higher 22∶6n−3 than infants fed formula without 22∶6n−3. Formula with 0.24% 22∶6n−3, however, resulted in higher plasma phospholipid 22∶6n−3 than in breast‐fed infants at 16, but not 4 or 8 wk of age. Plasma and RBC phospholipid 20∶4n−6 was lower in formula‐fed than breast‐fed infants, but no differences in growth were found. Higher blood lipid C20 and C22 n−6 and n−3 fatty acids in infants fed formula with 20% 18∶2n−6 and 2.4% 18∶3n−3 compared with 32% 18∶2n−6 and 4.9% 18∶3n−3 show the increase in blood lipid 22∶6n−3 in response to dietary 22∶6n−3 depending on other fatty acids in the formula.
Diversity of the polar lipids of the food‐borne pathogenListeria monocytogenes
Authors: Mastronicolis Sofia K. , German J. Bruce , Smith Gary M. 
Published: November 2006

AbstractListeria monocytogenes is a Gram‐positive bacterium that can adapt to high salinity and cold. Because the membrane lipids may play a role in its survival and adaptation, we have examined the polar lipids ofL. monocytogenes. Extraction of total lipids fromL. monocytogenes yielded 7±1 mg/mL wet cells. Polar lipids represented 64% of total lipids and contained 9% lipid‐phosphorus. Polar lipids were separated into 14 components by two‐dimensional thin‐layer chromatography. Eight components (88% of polar lipids) contained lipid‐phosphorus; among these was one major component (34% of polar lipids). Two other phospholipids were ninhydrin‐positive components and accounted for 15% of the polar lipids. Orcinol staining revealed two glyco‐ or sulfo‐lipids accounting for 9% of polar lipids. Five components (4% of polar lipids) were amino components free of phosphorus. The major component contained 46% of its fatty acids as 15:0anteiso, 24% as 17:0anteiso, and 11% as 15:0iso. The fatty acid profile of the remaining polar lipids was variable, consisting primarily of 16:0, 18:0, 15:0anteiso, and 17:0anteiso. Their unsaturation level was ≤20%; however, the major phosphoaminolipid component was 46% unsaturated. The ratios of 15:0anteiso/17:0anteiso and 15:0anteiso/15:0iso were similar in all classes, averaging 1.5 and 4.5, respectively. Since the adaptation process to stressful environments involves activation of a membrane transport system for the protectant glycine betaine, the membrane lipids may play a role in enabling transport.
An improved ultracentrifugation method for the separation of cholesterol carriers in bile
Authors: Ayyad Nariman , Cohen Bertram I. , Ohshima Akira , Mosbach Erwin H. 
Published: November 2006

AbstractVesicles and micelles, the major carriers of cholesterol in bile, play a role in the formation of cholesterol gallstones. A simple and rapid ultracentrifugation method was developed to isolate these biliary cholesterol carriers when only microliter amounts of bile were available. The proposed method employs a 46 to 0% sucrose density gradient, a NVT90 near‐vertical rotor, and a centrifugation time of one hour. As little as 25 μL of bile can be used with no disruption of the carriers. The method was validated by comparison with gel filtration column chromatography using 6 mM taurocholate in the elution buffer. The sucrose linear density gradient ultracentrifugation procedure described here is simple, fast, and compares favorably with the gel filtration chromatography method for the separation of cholesterol carriers from bile.