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21.
22.
以磁性壳聚糖纳米复合材料共价固定的褶皱假丝酵母脂肪酶为催化剂,以木质甾醇和油酸为原料,对木质甾醇油酸酯的酶法合成工艺条件进行了优化。得到的最佳工艺条件为:催化剂用量12.7%(以底物总质量计),油酸与木质甾醇物质的量比为2∶1,木质甾醇质量浓度为122.9 g/L,反应温度50℃,反应时间24 h。在该条件下,木质甾醇转化率为96.42%。对月桂酸、肉豆蔻酸、棕榈酸不同碳链长度的脂肪酸或混合脂肪酸进行酯化反应,木质甾醇的转化率可达96.67%~98.74%,催化剂使用5次时,转化率仍可达82.45%。 相似文献
23.
Hui Su Yoon Yu Jin Lee Byung Hee Kim Yangha Kim In-Hwan Kim 《Journal of the American Oil Chemists' Society》2023,100(3):215-224
γ-Linolenic acid (GLA) rich triacylglycerol (TAG) was successfully synthesized from glyceride, instead of glycerol, and fatty acid (FA) via Lipozyme TL IM-catalyzed esterification as a novel strategy. In the first step, GLA was enriched into glyceride fraction from borage oil by Candida rugosa lipase-catalyzed hydrolysis. The glyceride was separated from the reaction mixture by molecular distillation. GLA was enriched from 20.64% in borage oil to 45.94% in the glyceride fraction under optimum conditions. In the second step, the Lipozyme TL IM-catalyzed synthesis of TAG was carried out with the glyceride, and the FA obtained by saponification of a portion of the glyceride. The optimum conditions were the temperature of 50°C, the enzyme loading of 10%, and the vacuum level of 20 mmHg, respectively. The maximum TAG content of approximately 92% was achieved after 12 h under the optimum conditions. 相似文献
24.
Toshihiro Nagao Yuji Shimada Yoshie Yamauchi-Sato Takaya Yamamoto Masaaki Kasai Kentaro Tsutsumi Akio Sugihara Yoshio Tominaga 《Journal of the American Oil Chemists' Society》2002,79(3):303-308
A commercial product of CLA contains almost equal amounts of cis-9,trans-11 (c9,t11)-CLA and trans-10,cis-12 (t10,c12)-CLA. We attempted to enrich the two isomers by a two-step selective esterification using Candida rugosa lipase that acted on c9,t11-CLA more strongly than on t10,c12-CLA. An FFA mixture containing CLA isomers was esterified with an equimolar amount of lauryl alcohol in a mixture of 20%
water and the lipase. When the esterification of total FA reached 50%, two isomers were fractionated in a good yield: t10,c12-CLA was enriched in FFA, and c9,t11-CLA was recovered in lauryl esters. The FFA were esterified again to enrich t10,c12-CLA. At 27.3% esterification of total FA, the t10,c12-CLA content in FFA increased to 64.8 wt% with 89.3% recovery: The ratio of the content of t10,c12-CLA to that of two isomers was 95.9%. Lauryl esters obtained by the single esterification were employed for enrichment
of c9,t11-CLA. After the esters were hydrolyzed, the resulting FFA were esterified again with lauryl alcohol. At 62.0% esterification
of total FA, the c9,t11-CLA content in lauryl esters increased to 73.3 wt% with 79.4% recovery: The ratio of the content of c9,t11-CLA to that of two isomers was 95.6%. In a 600-g-scale purification, molecular distillation was effective in separating
the reaction mixture into lauryl alcohol, FFA, and lauryl ester fractions. 相似文献
25.
S.?P.?J.?Namal Senanayake Fereidoon?ShahidiEmail author 《Journal of the American Oil Chemists' Society》2002,79(10):1003-1013
This study utilized γ-linolenic acid (18∶3n−6; GLA)-rich borage oil (BO) and evening primrose oil (EPO) for the synthesis
of structured lipids (SL) and compared the oxidative stability of the products with those of unmodified BO and EPO as controls.
Immobilized Novozym 435 lipase from Candida antarctica was used as the biocatalyst for SL production. BO or EPO eas enzymatically modified with docosahexaenoic acid (22∶6n−3; DHA),
as the acyl donor, to produce SI. The SI were characterized and their oxidative stabilities evaluated. Among the oils examined,
SL gave rise to higher quantities (P≤0.05) of conjugated dienes, TBARS, and headspace volatiles as compared to their unmodified counterparts. Results indicated
that modified oils were less stable than their unmodified counterparts. The double bond index (DBI) and methylene bridge index
(MBI) of oils decreased (P<0.05) during oxidation in the more unsaturated oils. An attempt was made to correlate various parameters of oxidation with
DBI and MBI of oils; correlation coefficients (−r) were within the range of 0.574–0.973. This suggests that indicators such as DBI and MBI can reflect oxidative stability
of oils. 相似文献
26.
Yukihisa Tanaka Jiro Hirano Tadashi Funada 《Journal of the American Oil Chemists' Society》1992,69(12):1210-1214
In an attempt to concentrate the content of DHA (docosahexaenoic acid) in a glyceride mixture containing triglyceride, diglyceride
and monoglyceride, fish oil was hydrolyzed with six kinds of microbial lipase. After the hydrolysis, free fatty acid was removed
and fatty acid components of the glyceride mixtures were analyzed. When the hydrolysis withCandida cylindracea lipase was 70% complete, the DHA content in the glyceride mixture was three times more than that in the original fish oil.
The EPA (eicosapentaenoic acid) content became almost 70% of the original fish oil. Hydrolysis with other lipases did not
result in an increase in the DHA content in the glyceride mixtures. Hydrolysis of DHA-rich tuna oil (DHA content is about
25%) withCandida cylindracea lipase resulted in 53% DHA in the glyceride mixture. The EPA content, however, remained close to that of the original tuna
oil. In this report, the acyl chain specificity of lipases is evaluated in terms of hydrolysis resistant value (HRV). HRV
is the ratio between the DHA contents in the glyceride mixture of hydrolyzed oil and original oil. HRV clearly indicates differences
in hydrolysis between DHA and other fatty acids (e.g., saturated and monoenoic acids). 相似文献
27.
Potent Synergy between Spirocyclic Pyrrolidinoindolinones and Fluconazole against Candida albicans 下载免费PDF全文
Ilandari Dewage Udara Anulal Premachandra Kevin A. Scott Chengtian Shen Dr. Fuqiang Wang Shelley Lane Prof. Dr. Haoping Liu Prof. Dr. David L. Van Vranken 《ChemMedChem》2015,10(10):1672-1686
A spiroindolinone, (1S,3R,3aR,6aS)‐1‐benzyl‐6′‐chloro‐5‐(4‐fluorophenyl)‐7′‐methylspiro[1,2,3a,6a‐tetrahydropyrrolo[3,4‐c]pyrrole‐3,3′‐1H‐indole]‐2′,4,6‐trione, was previously reported to enhance the antifungal effect of fluconazole against Candida albicans. A diastereomer of this compound was synthesized, along with various analogues. Many of the compounds were shown to enhance the antifungal effect of fluconazole against C. albicans, some with exquisite potency. One spirocyclic piperazine derivative, which we have named synazo‐1, was found to enhance the effect of fluconazole with an EC50 value of 300 pM against a susceptible strain of C. albicans and going as low as 2 nM against some resistant strains. Synazo‐1 exhibits true synergy with fluconazole, with an FIC index below 0.5 in the strains tested. Synazo‐1 exhibited low toxicity in mammalian cells relative to the concentrations required for antifungal synergy. 相似文献
28.
29.
Roxana Irimescu Kiyomi Furihata Kazuhiko Hata Yugo Iwasaki Tsuneo Yamane 《Journal of the American Oil Chemists' Society》2001,78(3):285-290
A highly efficient enzymatic method for the synthesis of regioisomerically pure 1,3-dicapryloyl-2-docosahexaenoyl glycerol
(CDC) in two steps was established. 2-Monoglyceride (2-MG) formation by ethanolysis of tridocosahexaenoylglycerol (DDD) with
immobilized Candida antarctica lipase (Novozym 435) as catalyst was the key step of the synthesis. CDC was finally obtained by reesterification of 2-MG
with ethylcaprylate (EtC) catalyzed by Rhizomucor miehei lipase (Lipozyme IM). The regiospecificity of Novozym 435 depended on the type of reaction and the initial composition of
the reaction medium. It displayed strict 1,3-regiospecificity for ethanolysis at a high excess of ethanol in the reaction
mixture although it displayed no regiospecificity in transesterification and esterification reactions. The highest yield of
CDC (85.4%) was obtained by ethanolysis at a 4∶1 weight ratio of ethanol/DDD for 6 h followed by reesterification at a 20∶1
molar ratio of EtC/initial DDD for 1.5 h. The regioisomeric purity of CDC was 100%. Good results were obtained also for the
synthesis of 1,3-dicapryloyl-eicosapentaenoylglycerol (CEC) by the same method: 84.2% yield and 99.8% regioisomeric purity
at the same reactant ratios as above. The yield of the reesterification step and the regioisomeric purity of the product were
influenced by the molar ratio of the reactants for both CDC and CEC syntheses: higher excess of EtC favored higher yields
and regioisomeric purity of the products. 相似文献
30.
Taeko Izumi Yoshihiro Yagimuma Masanori Haga 《Journal of the American Oil Chemists' Society》1997,74(7):875-878
Enyzmatic amidation of the primary amines β-alanine ethyl ester and 3-aminopropionitrile with methyl laurate by means of immobilized
lipase (Candida antarctica lipase, CAL) resulted in the formation in good yield of N-lauroyl-β-alanine ethyl ester and 3-(N-lauroylamino)-propionitrile, respectively. When 3-amino-propionitrile was used as substrate, diisopropyl ether was a suitable
solvent. Changing the reaction temperature (12–80°C) did not affect the yields, and room temperature was a suitable temperature
for this reaction. In the investigation of reaction conditions, the use of equimolar amounts (5 mmol) of substrate and ester,
along with 0.5 g of CAL, in diisopropyl ether gave the best yield (99.3%) after 24 h of incubation at 24°C. The enzyme activity
in the amidation reaction did not decrease even after six uses. With β-alanine ethyl ester hydrochloride as substrate, diisopropyl
ether was unsuited as a solvent owing to the low solubility of the substrate in this solvent.
In this reaction, the best yield (82.0%) was attained by using dioxane as solvent. CAL achieved higher extents of amide synthesis
with long-chain than with short-chain ester substrates. The enzyme accepted only nonbulky primary amines as substrates. 相似文献