生物转化脂肪酸合成ω-羟基酸和ω-氨基酸研究进展

ω-羟基脂肪酸和ω-氨基脂肪酸可广泛用于聚酯、聚酰胺等高分子的合成以及润滑油、生物燃料、医药中间体等化工产品的生产。近年来,以自然界丰富的可再生资源脂肪酸为绿色原料,生产这类可降解的生物基材料及化学品引起了人们的广泛兴趣,其中从植物油中的油酸、亚油酸等脂肪酸出发生产中链脂肪酸及其羟基、氨基衍生物的非天然生物催化反应也越来越丰富,是合成生物学技术在油脂资源转化方面的一个重要应用。综述了近年来中链ω-羟基脂肪酸与ω-氨基脂肪酸生物合成的研究进展,展示了通过多酶级联催化反应将可再生的脂肪酸生物转化,可持续生产9-羟基壬酸、6-氨基己酸、ω-氨基十二烷酸等高附加值精细化学品的合成路径和应用前景。     

天然植物油脂在化妆品中的应用

叙述了油脂在化妆品中的功效性评价及天然植物油脂的市场现状,介绍了植物油脂的重要活性物ω-3和ω-6脂肪酸）的皮肤功效及天然植物油脂的重要来源。指出,以植物油脂为原料的天然化妆品将越来越受到消费者喜爱。     

原料药与制剂

n-3脂肪酸市场有待规范 市场蕴藏空间 n-3脂肪酸,全称是n-3系多不饱和脂肪酸（n-3 PUFAs）,因多不饱和脂肪酸结构中第1个不饱和键出现在碳链甲基端的第3位而得名,也称ω-3多不饱和脂肪酸,包括ALA（α-亚麻酸）、EPA（二十碳五烯酸）、DHA（二十二碳六烯酸）、DPA（二十二碳五烯酸）,富含于某些植物油和海洋产品中。     

脂肪酸催化加氢制备长链烷烃研究进展

可再生的脂肪酸等脂质通过催化加氢处理转化为长链烷烃等高值化学品,对实现生物质资源的充分利用,缓解化石能源的过度消耗带来的环境和能源等诸多问题都有重要意义。作者首先介绍了脂肪酸(酯)向长链烷烃转化过程中的热催化手段和常见催化剂,并对该过程中涉及的催化过程与催化机理进行简单总结;随后介绍了光催化与光热催化脂肪酸转化过程的研究进展;最后,介绍了脂肪酸(酯)催化转化为长链烷烃这一过程的未来前景和当前的主要挑战。     

固定化Pseudovibrio-ω-转氨酶催化合成(4S)-四氢萘酮

舍曲林是一种重要的选择性5’-羟色胺再摄取抑制剂（SSRI）类抗抑郁药物,已经在全球抑郁症治疗中起到了重要的作用。（4S）-四氢萘酮是合成舍曲林的关键中间体,其供应受限于缺乏操作简单且环境友好的手性拆分路线。假单胞菌ω-转氨酶（Pseudovibrio-ω-Transaminase,P-ω-TA）是一种来源于海绵假单胞菌Pseudovibrio sp. WM33,具有吡哆醛-5’-磷酸（PLP）依赖性的转氨酶,对（4S）-四氢萘酮表现出良好的手性拆分能力,可将（1S,4S）-去甲基舍曲林转化为（4S）-四氢萘酮,但该游离酶在应用时面临酶制备过程复杂、只能单次使用和稳定性差等问题,使用成本高。本研究以T4噬菌体衣壳作为载体,探索了P-ω-TA的自组装固定化及生物催化回收利用。通过将P-ω-TA融合到T4的非必需小外壳蛋白（Soc）上,实现了酶在T4衣壳上的亲和固定,且拷贝数较高。固定化的P-ω-TA保持了完整的活性,可通过离心操作轻松回收并进行重复使用。在五次回收和重复使用过程中,每轮酶活性的平均回收率均大于93%。经验证,固定化P-ω-TA保持了在底物手性中心处的（S）-型选择性拆分以及对（1S,4S）-去甲基舍曲林的催化能力。本研究建立的固定化P-ω-TA方法降低了对（4S）-四氢萘酮手性拆分催化成本,并有助于建立一条更环保的舍曲林合成路线。关键词：假单胞菌ω-转氨酶;T4噬菌体;手性拆分;酶固定化;舍曲林中图分类号：Q814.2 文献标识码： A 文章编号：     

蒜头果油中长链脂肪酸选择性合成大环内酯

研究了蒜头果油脂中长链不饱和脂肪酸的臭氧氧化以及ω-羟基脂肪酸的催化关环合成大环内酯,考察了臭氧氧化切断双键选择性和大环内酯化选择性。结果表明,不饱和脂肪酸的碳链越长,越有利于臭氧氧化反应和生成大环内酯。蒜头果油脂合成大环内酯的产率为:环十五内酯36.9%,环十三内酯为22.4%,环十一内酯1.0%,并探讨了蒜头果油脂中油酸的反应特性。     

酶法富集分离ω-3PUFAs的研究进展

多元不饱和脂肪酸(ω-3PUFAs)是具有多种生理活性的功能因子,对人体健康有重要作用。由于ω-3PUFAs大多来源于深海鱼油或藻类油脂,含量远不能达到营养品甚至药用的要求,有效富集ω-3PUFAs已成为近年来的研究热点。文章综述了利用脂肪酶选择性催化进行ω-3PUFAs富集的有关研究进展,对酶促油脂选择性水解反应,选择性转酯反应和选择性酯化反应以及不同方法组合进行ω-3PUFAs富集的反应机理以及应用进行了综述,进而对酶法生产高含量ω-3PUFAs的应用前景进行了展望。     

ω-转氨酶制备手性胺的研究进展

简要介绍了ω-转氨酶的催化机理、菌株来源以及目前国内外利用ω-转氨酶催化拆分或合成手性胺类化合物的研究进展。阐述了转氨酶生产手性胺中遇到的问题与解决方法,同时介绍了ω-转氨酶的固定化研究情况。最后对ω-转氨酶的发展前景进行了展望。     

ω-氯己基环氧丙基醚及其均聚物的合成

ω-卤烷基环氧丙基醚是合成其它ω-取代烷基环氧丙基醚的原料,又是合成含有ω-卤素侧基的聚醚的单体。从ω-取代烷基环氧丙基醚或含有ω-卤素的聚醚出发,可以合成各种以聚醚为主链的功能高聚物,如粘合剂、聚电解质、高分子负载络合催化剂等。但是,已有的报导均限于各种含β-功能基的环氧丙基醚及其聚合物。考虑到功能基与主链的距离将影响功能高聚物的性能,我们合成了ω-氯己基环氧丙基醚及其均聚物和ω-氯己基环氧丙基醚与其它环氧单体共聚的聚醚,进而还合成了各种以聚醚为载体的高分子络合催化剂。本文报导的是ω-氯己基环氧丙基醚及其均聚物的合成。合成途径如下:     

毛细管色谱分析植物油中脂肪酸组成

毛细管色谱分析植物油中脂肪酸组成李宝瑛，孙春梅（北京化工学院应用化学系１０００２９）随着油脂化学的发展，近年来发现ω３系列脂肪酸所特有的生理活性，如亚麻酸具有下列药理作用［１］：①增强脑功能，促进智力发育；②改善神经功能和视网膜功能；③具有降血脂和预...     

Trans fatty acids: foods and effects on health

Trans fatty acids can be found in foods derived from ruminant animals and foods that contain partially hydrogenated fat such as fast foods. The consumption of trans fatty acids is larger in the United States, Canada, and some European countries than in Japan and Mediterranean countries. The incidence of coronary heart diseases is higher in countries where the consumption of trans fatty is high. Studies show that trans fatty acids can contribute to increase LDL and lipoprotein [a], and to reduce the levels of HDL. In addition, trans isomeric seems to inhibit the action of desaturase enzymes of essential fatty acids (A5- and A6-desaturase) by holding back the biosynthesis of important fatty acids such as arachidonic acid and docosahexaenoic acid (DHA). With respect to pregnant women's and infant's health, concentrations of trans fatty acids ingested by the mother are associated to concentrations found in the maternal milk. Besides the milk, the trans fatty acids can be transferred to the newly born through the placenta. Studies suggest that trans fatty acids can affect intrauterine growth due to the inhibition of the conversion of essential fatty acids by desaturase enzymes. The inhibition of DHA can also cause early atherosclerosis lesion. However, studies on the effects of trans fatty acids on health are still inconclusive and there are no current recommendations on their consumption. Additionally, in Brazil, studies to determine the composition of trans isomeric in foods are still incipient, which indicates a great need of research in this area.     

Enzymatic methylation of canola oil deodorizer distillate

Methylation of canola oil deodorizer distillate catalyzed by a nonspecific lipase was investigated. The conversion of fatty acids to methyl esters has been optimized by using a statistical design. Up to 96.5% conversion of fatty acids to their methyl esters has been achieved without the aid of vacuum or any water-removing agent. The effects of temperature, ratio of the reactants (methanol: fatty acids in the deodorizer distillate) and enzyme concentration on the equilibrium conversion were studied. The temperature and ratio of the reactants showed a significant effect on the conversion of fatty acids to methyl esters and they exhibited a strong interactive effect. Enzyme concentration in the range of 2.7% to 4.3% did not show a significant effect on the equilibrium conversion of fatty acids. Greater than 95% conversion of fatty acids to methyl esters was achieved at temperatures around 50°C and at a ratio of the reactants between 1.8 and 2.0. The inhibitory effect of hydrophilic methanol on the enzyme activity was largely reduced by working at the lower temperature range (around 50°C).     

Studies of the fatty acid specificity of the lipase fromRhizomucor miehei toward 20:1n-9, 20:5n-3, 22:1n-9 and 22:6n-3

The fatty acid specificity of the lipase fromRhizomucor miehei toward 20:1n-9, 20:5n-3, 22:1n-9 and 22:6n-3 has been determined by comparing the alcoholysis (byn-propanol) of various mixtures of C₂₀ and C₂₂ fatty acids (FFA) or the corresponding ethyl esters (FAEE) inn-heptane. For all the fatty acids examined, the degree of conversion was much higher when using FFA rather than FAEE. When comparing the experiments with either single FAEE or FAEE mixtures, it was found for all four fatty acids that the degree of conversion depended on whether the FAEE was alone or together with other fatty acids in the reaction mixture. The lipase showed a strong specificity toward 20:1n-9, whereas the polyunsaturated fatty acids were much poorer substrates, especially 22:6n-3. The degrees of conversion for the two n-3 fatty acids show a clear preference for 20:5n-3 over 22:6n-3, not only when present alone but also in the different mixtures examined. The results obtained in the present experiments therefore suggest that when using the lipase fromR. miehei for enrichment of fish oils with n-3 fatty acids, it should not only be possible to diminish the content of 20:1 and 22:1 present in the outer positions in the triacylglycerols, but also to incorporate relatively more 20:5n-3 than 22:6n-3 into the triglycerides.     

New process for the production of branched-chain fatty acids

Fatty acids are the primary natural starting materials for the production of surfactant and detergent molecules. Derived from vegetable (oil) and animal (fat) triglyceride sources, the fatty acids are linear aliphatic carboxylic acids. Industrial interest in branched-chain fatty acids is driven by the needs for products with enhanced performance benefits including higher solubility, ease of handling, better hard water tolerance, and improved oxidative stability. Therefore, catalytic processes have been developed for the conversion of linear fatty acids to branched ones. High yields of branched acids are obtained from unsaturated fatty acids over acidic zeolites, particularly those with large pores. Fatty esters also are readily isomerized to branched ones by means of the same catalyst and process. It is postulated that the isomerization of fatty acids proceeds through three- and four-membered ring carbocation intermediates formed inside the largepore zeolites. This is supported by evidence of methyl and ethyl branching in the primary and final products. The total number of carbon atoms in the fatty acid molecule is unchanged. Surfactants derived from branched fatty acids show favorable physical properties, including a lower viscosity and improved handling, even as intended performance characteristics are maintained.     

Chemoenzymatic epoxidation of unsaturated fatty acid esters and plant oils

In the presence of an immobilized lipase fromCandida antacrtica (Novozym 435^R) fatty acids are converted to peroxy acids by the reaction with hydrogen peroxide. In a similar reaction, fatty acid esters are perhydrolyzed to peroxy acids. Unsaturated fatty acid esters subsequently epoxidize themselves, and in this way epoxidized plant oils can be prepared with good yields (rapeseed oil 91%, sunflower oil 88%, linseed oil 80%). The hydrolysis of the plant oil to mono- and diglycerides can be suppressed by the addition of a small amount of free fatty acids. Rapeseed oil methyl ester can also be epoxidized; the conversion of C=C-bonds is 95%, and the composition of the epoxy fatty acid methyl esters corresponds to the composition of the unsaturated methyl esters in the substrate. Based partly on a lecture at the 86th AOCS Annual Meeting & Expo, San Antonio, Texas, May 7–11, 1995.     

The preparation of fatty acid chlorides

Summary Fatty acid chlorides of lauric, myristic, palmitic, stearic, oleic, elaidic, and linoleic acids were prepared using phosphorus tri- and pentachlorides, oxalyl chloride, and thionyl chloride as chlorinating agents. On the basis of yields, ease of handling, and cost of reagent, phosphorus tri- and pentachlorides are superior to other chlorinating agents for the preparation of the higher fatty acid chlorides for use as intermediates in the preparation of pure saturated fatty acid glycerides of known structure. The unsaturated fatty acid chlorides are, however, best prepared from oxalyl chloride. The use of phosgene, which has been patented for the preparation of acid chlorides, failed to effect efficient conversion of the higher fatty acids to the corresponding chlorides. The analysis of the fatty acid chlorides by conversion to anilides provides a simple and easy means for ascertaining the extent of conversion of fatty acids to chlorides. By means of this method it is possible to follow readily the course of the reaction in order to determine when complete conversion of fatty acid to fatty acid chloride has been effected. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

The effect of antioxidant deficiency on tissue lipid composition in the rat. I. Gastrocnemius and quadriceps muscle

The gastrocnemius and quadriceps muscle phospholipids of the antioxidant-deficient rat fed a source of both linoleate and linolenate showed a progressive net increase in arachidonate, a progressive net decrease in all other polyunsaturated fatty acids, and there was a concomitant accumulation of fluorescent pigment of the lipofuscin or ceroid type in the tissue. An increased incorporation of intraperitoneally injected, isotopically labeled acetate into not only arachidonate but also the other higher polyunsaturated fatty acids, was observed. The net loss of the higher polyunsaturated fatty acids from the membrane lipids (presumably via lipid peroxidation) apparently was partially compensated by a homeostatic mechanism which involved conversion of the available precursors, linoleate and linolenate, to the higher polyunsaturated fatty acids. The rates of decrease of the polyunsaturated fatty acids in the muscle phospholipids and accumulation of fluorescent pigment in the tissue were correlated with the rate of production of creatinuria.     

均相法制备生物柴油的研究

研究了添加四氢呋喃(THF)为共溶剂酸催化一步法酯交换制备生物柴油的实验过程,考察了醇油比、THF的添加量、原料中水及游离酸含量对反应的影响.结果表明,随着醇油摩尔比或THF的加量增大,转化率、收率均增大,酸价降低,最佳醇油摩尔比为21:1,最佳THF的添加质量分数为35%;原料中的水含量对于酯交换反应的副作用较大,随着水含量的增大,转化率明显降低、酸价升高,水质量分数达到1.6%以后转化率低于90%;原料中游离酸含量对反应过程影响较小,游离酸含量增大,转化率和酸价均略有增大.     

Synthesis and physical properties of isostearic acids and their esters

Saturated branched‐chain fatty acids (sbc‐FAs) are found as minor constituents in several natural fats and oils. Sbc‐FAs are of interest since they have lower melting points than their linear counterparts and exhibit good oxidative stability; properties that make them ideally suited in a number of applications. We (and others) have previously synthesized sbc‐FAs by clay‐ or zeolite‐catalyzed isomerization of unsaturated linear‐chain fatty acids (ulc‐FAs) to unsaturated branched‐chain fatty acids (ubc‐FAs) that were subsequently hydrogenated to the desired sbc‐FAs. These acid‐catalyzed isomerization reactions, however, proceed in moderate conversion and selectivity. Recently, our group found that H‐Ferrierite zeolite catalyst isomerized ulc‐FAs to their branched‐chain counterparts in high conversion (>95%) and selectivity (85%). This paper reports the use of this type of catalyst for the preparation of a series of sbc‐FAs and their ester derivatives. Selected physical properties of these branched acids and esters such as cloud point (CP) and pour point (PP), cold filter plugging point (CFPP), viscosity index (VI), thermo‐oxidation stability, iodine value, and lubricity are also reported.     

Detection of 430 Fatty Acid Methyl Esters from a Transesterified Butter Sample

Milk fat is known to contain one of the highest number of fatty acids of all edible oils. Some of these fatty acids are known to be valuable (e.g. conjugated linoleic acids, furan fatty acid) and other as undesirable (e.g. saturated and some trans-fatty acids) food ingredients. However, a comprehensive picture on the presence of many trace fatty acids has not been achieved. For this reason we have developed an analysis scheme based on the conversion of the fatty acids into methyl esters. The fatty acid methyl esters were then fractionated by urea complexation. Both the filtrate of the urea complexation (~4 % of the sample weight) and the original sample were fractionated by high-speed counter-current chromatography (HSCCC). The resulting fractions were analyzed by GC/MS analysis. With this method 430 fatty acids were detected in one single butter sample. More than 230 fatty acids had two or more double bonds. In addition to the widely known spectrum of fatty acids we also detected a range of cyclohexyl fatty acids (five homologues) and methyl-branched fatty acids (including short chain and even-numbered anteiso-fatty acids), conjugated tetradecadienoic acids along with the novel ω-oxo-fatty acids (seven homologues). The reported relative retention time on the polar column may serve as a data base for the screening of other samples for this profusion of fatty acids.