Rapid separation of triacylglycerol positional isomers binding two saturated Fatty acids using octacocyl silylation column

The rapid separation of a triacylglycerol positional isomer (TAG-PI) pair was examined via high-performance liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometry using an octacocyl silylation (C28) column. A TAG-PI pair binding two palmitic acids and one fatty acid that structurally differs from palmitic acid was separated at 10°C and 15°C using acetone as the mobile phase. However, the TAG-PI pair binding two unsaturated fatty acids and one saturated fatty acid was not separated by the C28 column. The results indicate that the structures of the two palmitic acids (saturated fatty acids) and the other fatty acid at the α or β position in TAG play an important role in the separation of the TAG-PI pair, and that the structure of the fatty acid needs to be considerably different from that of the palmitic acid, specifically in terms of the chain length or the location of the double bond.     

有机介质中脂肪酶促动力学拆发外消旋1-三甲基硅乙醇

The enantioselective esterification of racemic 1-trimethylsilylethanol with acids catalyzed by lipase in organic solvent was successfully performed. The influence of some factors on the reaction was investigated. Among the four lipases explored, Candlda rugosa lipase (CRL) showed the highest activity and enantioselectivity. Octanoic acid was the best acyl donor among the eleven acids studied and n-hexane was the most suitable medium for the reaction. The optimum shaking rate and temperature were found to be 150 r-rain-i and 20~(3 to 30~C, respectively.The enantiomeric excess of the remaining (S)-(-)-1-trimethylsilylethanol was 93% when substrate conversion was 53% upon incubation of the reaction mixture at 30~C, 150 r-rain-i for 12 h.     

Conversion of oleic acid to 10-ketostearic acid by aStaphylococcus species

In the course of using microorganisms to produce value-added products from soybean oil or its fatty acids, a culture contaminant was isolated and tentatively identified as aStaphylococcus species. This microorganism converts oleic acid (cis-9-octadecenoic acid) to 10-ketostearic acid (10-keto-octadecanoic acid) in growing cultures. Bioconversion was studied in two different media at temperatures from 30 to 41°C, with shaking at 150 rpm. Cells were grown in 50 mL of media for 24 h and then incubated with 0.25 g oleic acid for 24 h. Optimum conditions have allowed better than 90% conversion with 85% recovery. Unreacted oleic acid and 10-hydroxystearic acid (10-hydroxyoctadecanoic acid) are the only other compounds present in the ethyl ether extract of the fermentation broth.     

Dynamics of the Lipid Content and Biomass of <Emphasis Type="Italic">Calanus finmarchicus</Emphasis> (copepodite V) in a Norwegian Fjord

Calanus finmarchicus is the dominant zooplankton species in the North Atlantic. This zooplankton is also of interest for commercial harvesting due to its high abundance and biochemical contents. In the present study, copepodite stage V of C. finmarchicus was sampled at different depths from January to June in 2009, 2010 and 2011 in the Trondheimsfjord (63°29'N 10°18'E). The fatty acid composition was analyzed in individual copepods and in the seston. It was found that the fatty acid profile of copepods was related to the fatty acid profile of potential food sources. This study indicates that the onset of vertical migration of stage V, which was observed in May, has a strong link to the production of phytoplankton and lipid accumulation in C. finmarchicus. The content of 14:0 and 16:0 fatty acids in the specimens did not increase from February to May in surface waters. This suggests that these fatty acids in the diet were used as precursors for the biosynthesis of 20:1n-9 and 22:1n-11 fatty acids and fatty alcohols. A potential harvesting season of C. finmarchicus could be when the species is abundant in surface waters; the content of n-3 fatty acids will vary throughout this season. The peak abundance of C. finmarchicus in the spring varied substantially between the years studied.     

Solvent-Assisted Crystallization of Fatty Acid Alkyl Esters from Animal Fat

An easy and efficient method for the separation of saturated and unsaturated fatty acid mono alkyl esters, prepared from animal fat, was developed. The most efficient separation was achieved by the use of solvents such as methanol and acetone at low temperatures. The dilution of the alkyl esters with 10 times the amount of solvent (10:1 v/w) and storage of the mixture for 4 h at ?22 °C could be defined as optimum conditions. After filtration of the saturated fraction at the corresponding temperature very pure fractions were obtained. For fatty acid methyl esters deriving from tallow, with an initial content of saturated fatty acids of almost 50 %, a saturated ester fraction with only 5 % unsaturated fatty acids and an unsaturated ester fraction with about 9 % of saturated fatty acids could be obtained. The solvent easily could be recovered by distillation. In addition fatty acid ethyl, 1‐propyl, 2‐propyl, 1‐butyl, tert‐butyl and 3‐methyl‐1‐butyl esters were prepared and separated into saturated and unsaturated fractions. All fractions were analyzed according to the fatty acid compositions and showed similar or slightly worse results compared to the methyl esters. The cold filter plugging points of the unsaturated fractions were measured, showing the lowest value for the unsaturated methyl ester fraction at ?26 °C. The fractionation with the use of solvents is an easy tool in order to obtain fatty acid alkyl esters with excellent cold temperature behavior out of animal fat.     

Effects of temperature and temperature shift on docosahexaenoic acid production by the marine microalge Crypthecodinium cohnii

The effects of temperature and temperature shift on the fatty acid composition and docosahexaenoic acid (DHA, C22∶6n−3) content and productivity of the marine microalga Crypthecodinium cohnii ATCC 30556 were investigated. The microalga grew well over the entire range of temperatures (15–30°C) studied. High temperature favored the growth of the microalga with the highest specific growth rate of 0.092 h⁻¹ at 30°C. In contrast, low temperature favored the formation of polyunsaturated fatty acids. The highest DNA content was obtained at 15°C in the early stationary phase (i.e., 72h). In order to achieve high DHA productivity, a shift from high temperature to low temperature at a later stage of cultivation (i.e., 48h) was also attempted. A temperature shift from 25°C (for 48 h) to 15°C (for 24 h) resulted in an increase in cellular DHA content by 19.9% and productivity by 6.5% as compared to that maintained at 25°C (for 72 h).     

Characterization of Thermophilic Halotolerant Aeribacillus pallidus TD1 from Tao Dam Hot Spring, Thailand

The bacterial strain TD1 was isolated from Tao Dam hot spring in Thailand. Strain TD1 was Gram positive, rod-shaped, aerobic, motile, and endospore forming. The cell was 2.0-40 μm in length and about 0.4 μm in diameter. The optimum growth occurred at 55-60 °C and at pH 7-8. Strain TD1 was able to grow on medium containing up to 10% NaCl. The DNA G+C content was 38.9 mol%. The cellular fatty acid content was mainly C(16:0), which comprised 25.04% of the total amount of cellular fatty acid. 16S rDNA showed 99% identity to Aeribacillus pallidus DSM 3670(T). Bayesian tree analysis strongly supported the idea that strain TD1 is affiliated with genus Aeribacillus, as Aeribacillus pallidus strain TD1. Although the 16S rDNA of A. pallidus strain TD1 is similar to that of A. pallidus DSM 3670(T), some physiological properties and the cellular fatty acid profiles differ significantly. A. pallidus strain TD1 can produce extracellular pectate lyase, which has not been reported elsewhere for other bacterial strains in the genus Aeribacillus. A. pallidus strain TD1 may be a good candidate as a pectate lyase producer, which may have useful industrial applications.     

Production of eicosapentaenoic acid bySaprolegnia sp. 28YTF-1

Saprolegnia sp. 28YTF-1, isolated from a freshwater sample, is a potent producer of 5,8,11,14,17-cis-eicosapentaenoic acid (EPA). The fungus used various kinds of carbon sources, such as starch, dextrin, sucrose, glucose, and olive oil for growth, and olive oil was the best carbon source for EPA production. The EPA content reached 17 mg/g dry mycelium (0.25 mg/L) when the fungus was grown in a medium that contained 2.5% olive oil and 0.5% yeast extract, at pH 6.0 and 28°C for 6 d with shaking. Accompanying production of arachidonic acid (AA; 3.2 mg/g dry mycelia, EPA/AA = 5.1) and other ω6 polyunsaturated fatty acids was low. Both EPA content and EPA/AA ratio increased in parallel by lowering growth temperature. Triglyceride was the major mycelial lipid (ca. 84%), but EPA comprised only 2.2% of the total fatty acids of this lipid. About 40% of the EPA produced was found in polar lipids, such as phosphatidylethanolamine (EPA content, 28.2%), phosphatidylcholine (13.6%), and phosphatidylserine (21.2%).     

Enzymatic synthesis of phenyl fatty hydroxamic acids from canola and palm oils

Phenyl fatty hydroxamic acids (PFHAs) were synthesized from canola or palm oils and phenyl hydroxylamine (FHA) catalyzed by Lipozyme TL IM or RM IM. The reaction was carried out by shaking the reaction mixture at 120 rpm. The optimization was carried out by changing the reaction parameters, namely; temperature, organic solvent, amount and kind of enzyme, period of reaction and the mol ratio of reactants. The highest conversion was obtained when the reaction was carried out under the following conditions: temperature, 39°C; solvent, petroleum ether; kind and amount of lipase, 80 mg Lipozyme TL IM/mmol oil; reaction period, 72 h and FHA-oil ratio, 7.3 mmol FHA/ mmol oil. The highest conversion percentage of phenyl hydroxylaminolysis of the Ladan and Kristal brands commercial canola oils, palm stearin and palm kernel oils were 55.6, 52.2, 51.4 and 49.7 %, respectively.     

Combined extraction processes of lipid from Chlorella vulgaris microalgae: microwave prior to supercritical carbon dioxide extraction

Extraction yields and fatty acid profiles from freeze-dried Chlorella vulgaris by microwave pretreatment followed by supercritical carbon dioxide (MW-SCCO(2)) extraction were compared with those obtained by supercritical carbon dioxide extraction alone (SCCO(2)). Work performed with pressure range of 20-28 Mpa and temperature interval of 40-70 °C, gave the highest extraction yield (w/w dry weight) at 28 MPa/40 °C. MW-SCCO(2) allowed to obtain the highest extraction yield (4.73%) compared to SCCO(2) extraction alone (1.81%). Qualitative and quantitative analyses of microalgae oil showed that palmitic, oleic, linoleic and α-linolenic acid were the most abundant identified fatty acids. Oils obtained by MW-SCCO(2) extraction had the highest concentrations of fatty acids compared to SCCO(2) extraction without pretreatment. Native form, and microwave pretreated and untreated microalgae were observed by scanning electronic microscopy (SEM). SEM micrographs of pretreated microalgae present tearing wall agglomerates. After SCCO(2), microwave pretreated microalgae presented several micro cracks; while native form microalgae wall was slightly damaged.     

Heat Treatment and Chemical Composition of Fatty Acids and Rosin Acids Mixtures: Effects on Their Thermal Properties and Morphology

Mixtures of fatty acids and rosin acids are industrially important products utilized as a raw material for several purposes. Their thermal properties, especially cold stability and crystallization behavior is also important. Several fatty acid and rosin acid mixtures both from industrial products and from commercially available fatty and rosin acids were prepared and treated for 30 min at 80 °C under an inert atmosphere. Thereafter, the mixture was cooled to the desired temperature. Determination of the cloud point, chemical analysis of liquid and solid phase, thermal analysis by differential scanning calorimetry as well as morphology analysis by scanning electron microscopy were performed. The results revealed that crystallization was more rapid when it occurred at 10 °C compared to 25 °C. The crystal sizes increased with decreasing the crystallization temperature. Furthermore, crystals were of irregular shape and agglomerated when rapid cooling of the mixture occurred. Chemical analysis revealed that liquid phase was enriched with stearic acid, whereas crystals contained large amounts of abietic, dehydroabietic and linoleic acids. The cloud point of the mixtures increased with increasing amount of stearic and rosin acids. Dehydroabietic acid addition improved the cold stability of the synthetic fatty acid–rosin acids mixture.     

Temperature effects on in vitro lipid accumulation in asexual embryos ofTheobroma cacao L.

Asexual embryos of cacao were grown for 40–50 days in a modified Murashige and Skoog liquid medium with sucrose concentration increased stepwise from 3 to 27% at temperatures of 10, 17, 20, 23, 26, 29, 32 or 35 C. Temperature influenced overall embryo growth as well as lipid accumulation and composition. Maximum growth occurred at 29 C, whereas maximum lipid and fatty acid accumulation occurred at 26 C. The proportion of individual fatty acids as total fatty acids accumulated per asexual embryo was constant at each temperature but varied with temperature from 10 to 35 C. The fatty acid composition of asexual embryos grown at 26 C was the most similar to that of cocoa butter, the lipid from mature zygotic embryos produced in vivo.     

Increased proportion of medium chain fatty acids in nystatin-resistant yeast mutants

Fatty acid composition of phospholipids and steryl esters from four nystatin-resistant mutants ofSaccharomyces cerevisiae was compared to that from the wild strain. All the mutant strains which produce several ergosterol intermediates incorporated two-to three-fold as much medium chain fatty acids, especially 14:0 and 14:1 in phospholipids, and 12:0, 14:0 and 14:1 in steryl esters as the wild strain did. The increase in the relative amount of medium chain fatty acids in these mutants was found at all the growth temperatures and the growth phases examined, and in all the phospholipid species.     

The fatty acid composition of a Vibrio alginolyticus associated with the alga Cladophora coelothrix. Identification of the novel 9-methyl-10-hexadecenoic acid

The fatty acid composition of a new strain of Vibrio alginolyticus, found in the alga Cladophora coelothrix, was studied. Among 38 different fatty acids, a new fatty acid, 9-methyl-10-hexadecenoic acid and the unusual 11-methyl-12-octadecenoic acid, were identified. Linear alkylbenzene fatty acids, such as 10-phenyldecanoic acid, 12-phenyldodecanoic acid and 14-phenyltetradecanoic acid, were also found in V. alginolyticus. The alga contained 43% saturated fatty acids, and 28% C₁₆–C₂₀ polyunsaturated fatty acids of the n−3 and n−6 families.     

Lipase-catalyzed incorporation of oleic acid into melon seed oil

The ability of lipase PS30 (Pseudomonas sp.) to modify the fatty acid profile of melon seed oil by incorporation of oleic acid (18:1n-9) was investigated. The transesterification was carried out in hexane in an orbital shaking water bath at 55°C for 24 h with methyl oleate (70% pure) as acyl donor. Oleic acid content increased from 13.5% to 53%, and linoleic acid (18:2n-6) content decreased from 65% to 33%. The incorporation of oleic acid into melon seed oil by Pseudomonas sp. lipase helped balance the fatty acid profile of the oil in terms of monounsaturated (18:1n-9) and essential fatty acids (18:2n-6).     

The changes of phospholipid degradation in sea urchin gonads (Glyptocidaris crenularis) during cold storage at 4°C

Sea urchin gonads (SUGs) are rich in phospholipid (PL) which is easily oxidized and hydrolyzed during cold storage. PL changes were evaluated to clarify the quality changes of sea urchins during 72 h storage at 4°C. During storage at 4°C, PL content decreased, including phosphatidylethanolamine and phosphatidylinositol content decreased significantly and lysophosphatidylcholine (LPC) was detected after 36 h storage. At the same time, phospholipase C and phospholipase D remained active, and the content of free choline and free fatty acids increased, suggesting that PL was hydrolyzed. The addition of n-butanol inhibited the activity of phospholipases C and D, decrease of total PL content, and the production of LPC and free choline, indicating that phospholipase-mediated hydrolysis of PL in gonads occurred during refrigeration. The addition of vitamin E inhibited lipoxygenase, reduced lipid peroxidation (POV), and thiobarbituric acid reactive substances. It indicated that lipoxygenase in SUG mediated the oxidative degradation of PL during cold storage.     

Lipid and fatty acid compositions of a novel docosahexaenoic acid-producing marine bacterium

An unidentified bacterial strain, SCRC-21406, isolated from the intestine of a marine fish, Glossanodon semifasciatus, produced docosahexaenoic acid at 23% (mol/mol) [=28% (w/w)] of total fatty acids in a medium containing 0.5% (wt/vol) peptone and 0.1% (wt/vol) yeast extract at 12°C under atmospheric pressure. The cell yield was 0.43 g/L. The major lipids of the strain were phosphatidylethanolamine and phophatidylglycerol. Docosahexaenoic acid was localized at the sn-2 positions of both phospholipids. The amounts of polyunsaturated fatty acids other than docosahexaenoic acid were extremely small [<3% (mol/mol)]. Monousaturated fatty acids of the cis-7, cis-9 and cis-11 types were detected.     

Enzymatic synthesis of capric acid-rich structured lipids (MUM type) using Candida antarctica lipase

The objective of the work was to produce capric acid rich structured lipids starting from various Indian indigenous vegetable oils, such as rice bran, ground nut and mustard oils. Acidolysis reaction between individual vegetable oils and capric acid in one is to three molar ratios at 45 degree centigrade temperature was carried out using position specific Candida antarctica lipase so as to protect the Sn-2 position of the oils which are rich in unsaturated fatty acids. The incorporation of capric acid depended on the reaction time showing 6 % within 6 h and 30.8 % in 72 h with rice bran oil. Similarly, in ground nut oil incorporation of capric acid was 34.2 % in 72 h compared to 5.3 % in 6 h. Thus mustard oil showed much lower incorporation than the other two oils, with 3.3 % and 19.5 % in 6 and 72 h respectively. The incorporation of capric acid was influenced by the nature of the fatty acids present in the original oil. The fatty acid composition of Sn-2 position of the structured triacylglycerols of the three oils revealed that capric acid was mainly replacing the fatty acids occupying the Sn-1 and 3 positions of the triglyceride molecule.     

The effect of temperature on lipid classes and their fatty acid profiles inLipomyces starkeyi

The effect of environmental temperature on fatty acid contents of major lipid classes was determined inLipomyces starkeyi at 30, 20, and 10°C. When the temperature was reduced from 30 to 20°C, the linolenic acid content increased in phosphatidylcholine but fell with further reduction to 10°C. The relative contribution of phosphatidylcholine and phosphatidylethanolamine that contained the next lowest-melting fatty acids, palmitoleic and linoleic acids, increased on lowering the temperature from 20 to 10°C and, concomitantly, the combined phosphatidylinositol and phosphatidylserine fraction decreased, and triacylglycerols were accumulated.