皱褶假丝酵母脂肪酶催化合成VE阿魏酸酯的研究

本文研究了反胶束体系中利用褶皱假丝酵母脂肪酶催化维生素E和阿魏酸乙酯合成维生素E阿魏酸酯的反应。通过单因素试验利用褶皱假丝酵母脂肪酶在AOT-异辛烷-水反胶束体系中催化阿魏酸乙酯和维生素E反应136 h生成VE阿魏酸酯,并研究了含水率、转速、温度、缓冲液pH值、AOT的浓度等反应条件对VE阿魏酸酯合成的影响。通过均匀设计法设计实验,并对结果进行二次多项式逐步回归分析,得到一组最优合成的反应条件,即含水率10、AOT浓度80 mmol/L、缓冲液pH值5.0、温度25℃、转速270 rpm,VE阿魏酸酯的得率为15.36%。     

超声酶促合成维生素A棕榈酸酯

研究了超声辐照下,在有机溶剂中以固定化脂肪酶Novozym435催化合成维生素A棕榈酸酯。考察了影响合成维生素A棕榈酸酯反应的诸因素(溶剂、底物摩尔比、底物浓度、反应时间、酶量和超声功率),并优化了反应条件:在10mL的正己烷溶剂中,0.164g维生素A醋酸酯和0.32g棕榈酸,在酶与维生素A醋酸酯的质量比为1∶4的固定化脂肪酶Novozym435催化下,超声功率为90W,反应6h,酯化率可达82%。     

利用脂肪酶催化水相中酯合成反应的研究

本文通过研究不同种类的醇对于微生物脂肪酶催化的酯水解反应的抑制作用,对水相中酯合成反应的机理进行了初步的探讨,并对微生物脂肪酶催化的油酸 和甲醇的酯合成应进行了条件优化,使其酯合成效率达到了较为理想的水平。     

微生物脂肪酶及其催化合成芳香酯研究进展

微生物脂肪酶可以催化酯类化合物的分解、合成和酯交换，因而被广泛应用于食品、精细化工和医药等工业中，近年来，随着界面酶学、有机相催化以及固化技术的不断深入和发展，微生物脂肪酶的诸多新特性正在被发现，其应用领域也在不断拓展。国内外的研究结果表明，用微生物脂肪酶可以催化合成多种芳香酯，并且在有机相中微生物脂肪酶的催化活性和稳定性较水溶液中明显提高；用微生物脂肪酶催化合成芳香酯可以克服用化学方法合成带来的问题，是一种芳香酯合成的有效方法。     

酶法合成植物甾醇酯工艺的研究进展

植物甾醇酯是一类具有降低血清胆固醇、预防心血管疾病等功效的新型功能食品添加剂。脂肪酶催化合成植物甾醇酯的途径包括与脂肪酸直接酯化、与三酰甘油酯或脂肪酸甲酯进行转酯化。介绍了国内外近年来脂肪酶催化合成植物甾醇酯的方法,并展望其开发前景,为研发环保、高效、可靠、安全的植物甾醇酯合成技术提供思路。     

均匀设计法优化α-生育酚阿魏酸酯薄层色谱展开剂系统

应用均匀实验设计及其数据处理,对脂肪酶催化维生素E与阿魏酸乙酯转酯生成维生素E阿魏酸酯的薄层色谱展开剂系统进行优化.使脂肪酶生物催化合成的目标产物能够清晰地从薄层色谱中分离出来,并在薄层色谱扫描仪中进行准确的定量研究.当苯:乙醚:二氯甲烷:正已烷为4.528:7.692:6.894:6.144(V/V)时,可获得最佳分离效果.     

非水相中脂肪酶催化合成乙酸薄荷酯

研究了脂肪酶(candida rugosa lipase,CRL)在有机溶剂中催化薄荷醇与乙酸进行酯化反应的条件.探讨了脂肪酶加入量、溶剂、薄荷醇与乙酸摩尔比、底物浓度、温度等因素对脂肪酶催化合成乙酸薄荷酯的影响,并利用红外光谱、GC-MS、气相色谱等方法对合成的产物进行了表征.结果显示,合成的产物为乙酸薄荷酯.当溶剂为正己烷、脂肪酶量为1.2%(脂肪酶在薄荷醇和乙酸体系中的质量分数)、薄荷醇与乙酸的摩尔比为1:1、薄荷醇与乙酸的底物浓度均为0.1moL/L、温度为40℃、反应48h时,乙酸薄荷酯的酯合成转化率达92.4%.产物乙酸薄荷酯的色泽好、气味纯正.     

脂肪酶催化亚麻酸枇杷甾醇酯合成工艺优化

对脂肪酶催化亚麻酸枇杷甾醇酯工艺进行研究。以酯化率为参考指标,考察了在有机介质中不同脂肪酶催化合成亚麻酸枇杷甾醇酯,确定脂肪酶pseudomonas为催化剂。通过响应面分析法确定脂肪酶催化亚麻酸枇杷甾醇酯的最佳工艺,即在正己烷溶剂体系中,脂肪酶用量为7.8%,酸醇摩尔比为2.6∶1,反应温度为50.0℃,反应时间为52.5 h,此时亚麻酸枇杷甾醇酯的酯化率达到79.59%。     

有机相中脂肪酶的催化反应及其应用

有机相中脂肪酶的催化反应是非水相酶催化反应中一个重要方面,介绍了有机相中脂肪酶的催化反应及主要影响因素,并综述了脂肪酶的固定化及其固定方法。对有机相中固定化脂肪酶催化技术在脂肪酸酯的合成、食品、制药和新能源等领域的应用作了概述,最后对有机相中脂肪酶的催化技术进行了展望。     

无溶剂体系中固定化脂肪酶催化的维生素A棕榈酸酯的合成

研究了一种维生素A棕榈酸酯(vitamin A palmitate)的合成新途径。实验结果表明,棕榈酸甲酯作为酰基供体,在固定化酶催化下,在无溶剂体系中与维生素A醋酸酯通过酯交换反应生成维生素A棕榈酸酯。对无溶剂体系中催化合成维生素A棕榈酸酯的工艺进行优化,确定的最佳工艺参数为:转速250 r/min;温度60℃;固定化脂肪酶质量分数5%(占反应体系总重);棕榈酸甲酯和维生素A醋酸酯摩尔比1.3∶1。反应到达平衡的时间为3h,转化率为26.93%。此外,研究发现,在反应到达平衡后,连续抽真空,带走反应中产生的醋酸甲酯,反应平衡向产物生成的方向移动,继续反应12 h后,反应转化率可达80%,此时反应液中维生素A棕榈酸酯浓度可高达800 g/L。     

肉桂酸蔗糖酯的酶法制备及其抗菌活性

本文主要研究了利用脂肪酶催化蔗糖与肉桂酸合成制备肉桂酸蔗糖酯的过程及其抗菌性能。该制备过程以DMAc/叔戊醇双溶剂体系为反应介质,用以溶解极性底物糖并保持脂肪酶的良好活性,同时探索了混合溶剂体积比和反应温度对酶法合成的影响。对产物的红外光谱分析,表明蔗糖与肉桂酸在脂肪酶催化下发生了酯化反应;进一步对产物的13C-NMR分析,表明酯化反应发生在蔗糖的C-6位点上;对产物的TGA分析,表明制备的肉桂酸蔗糖酯具有较高的热稳定性。同时,酯化产物对大肠杆菌和白地霉具有明显的抑制作用,其抑菌率分别为97.83%和96.04%。此外,肉桂酸蔗糖酯还具有良好的保湿效果,保水率为76%。综合评价产物肉桂酸蔗糖酯的抑菌性能、热稳定性和两亲特性,其在食品、日化等领域将具有广阔的应用前景。     

咖啡酸维生素C酯的合成、抑菌活性和抗氧化性研究

研究了以3,4-二羟基苯甲醛、丙二酸和维生素C为原料,经过Knoevenagel缩合和直接酯化一锅法合成咖啡酸维生素C酯的方法,并考察了咖啡酸维生素C酯的抑菌活性和抗氧化性。在催化剂SO42-/ZrO2的作用下,3,4-二羟基苯甲醛与丙二酸首先发生Knoevenagel缩合生成咖啡酸,产物不需要分离,加入维生素C继续进行酯化反应,以85.1%的产率得到了咖啡酸维生素C酯,产物结构用1HNMR和IR进行确证。抑菌活性实验表明,咖啡酸维生素C酯对金黄色葡萄球菌、大肠杆菌、枯草杆菌、酿酒酵母、青霉、黄曲霉和黑曲霉均有较强的抑制作用,对细菌和酵母的抑制作用高于霉菌。抗氧化性实验表明,咖啡酸维生素C酯可以有效清除DPPH自由基和羟基自由基,清除效果明显好于维生素C。     

Regioselective acylation of flavonoid glucoside with aromatic acid by an enzymatic reaction system from cultured cells of Ipomoea batatas

The regioselective acylation of naturally occurring plant pigments with aromatic acids such as caffeic acid and p-coumaric acid was examined by an enzymatic reaction system from cultured cells of Ipomoea batatas. Isoquercitrin, a flavonoid glucoside, was converted to isoquercitrin 6'-O-caffeate by the enzymatic system. Chrysanthemin, an anthocyanin, was also acylated to the corresponding caffeate ester. This enzymatic method should prove useful for the synthesis of acylated flavonoid glucosides such as isoquercitrin caffeate, whose productivity is low using lipase-catalyzed transesterification.     

Lipase-catalyzed direct and regioselective acylation of flavonoid glucoside for mechanistic investigation of stable plant pigments

One-step and regioselective acylation of flavonoid glucosides was achieved by lipase-catalyzed transesterification in dry organic media. For example, isoquercitrin (quercetin 3-O-glucoside), one of the flavonol monoglucosides, was converted efficiently to the corresponding aromatic acid ester (isoquercitrin 6'-O-cinnamate) by a lipase with vinyl cinnamate as an acyl donor. The method described, which is the first allowing the direct synthesis of aromatic acid esters of flavonoid glucosides, can be applied to the acylation of other glucosides, including naringin, rutin, callistephin, and chrysanthemin.     

响应面法优化无溶剂体系酶法合成己酸乙酯

目的：探讨无溶剂体系酶法合成己酸乙酯的最佳工艺条件。方法：在单因素试验的基础上,以脂肪酶添加量、底物(己酸/乙醇)物质的量比、反应时间为影响因素,应用二次回归中心组合试验法进行三因素五水平试验,以己酸乙酯产率为评价指标,进行响应面分析。结果：无溶剂体系酶法合成己酸乙酯的最佳工艺条件为脂肪酶添加量0.5%、酸醇物质的量比1:1.3、反应时间12.2h、反应温度30℃,转速150r/min。在此条件下,己酸乙酯产率实际值为81.6%,与预测值相近。结论：采用中心组合试验设计--响应面法对无溶剂体系酶法合成己酸乙酯工艺条件进行优化合理可行。     

Comparative studies of immobilized lipase- and acid-catalyzed fatty acid methyl ester synthesis for seed lipid analysis

Fatty acids are one of the most important nutrients in food. Acid- or base-catalyzed transesterification methods are commonly used for the analysis of fatty acids. However, several drawbacks were reported for these methods, including the isomerization and degradation of fatty acids. Lipase-catalyzed reactions are usually undertaken at mild conditions, preventing such problems. In this study, commercial resin-bound lipase from Candida antartica was tested for possible application in fatty acid methyl ester analysis. Experimental parameters, including temperature, reaction time, and re-cycling were evaluated. The optimized condition was (5-10 mg lipid, 0.5 mL of MeOH, and 50 mg Novozyme 435 in 2 mL toluene, 80°C for 1 h). In optimized condition, the lipase-catalyzed methods yielded similar results with the chemical method. In overall, lipase-catalyzed transesterification can be a useful alternative to acid-catalyzed methods for fatty acid analysis.     

Lipase-catalyzed synthesis and characterization of myristoyl maltose ester

Myristoyl maltose ester was synthesized by lipase-catalyzed reaction of maltose and myristic acid. Influence of different reaction parameters, such as molecular sieve concentration, molar ratio of acid/sugar, enzyme concentration, reaction time, and reaction temperature, was studied. Under the optimum conditions of 20 g/L molecular sieve, 14% (w/w) lipase from Novozym 435, and acid/sugar molar ratio of 5:1 at 60 °C for 60 h, the highest conversion (90%) was achieved. The as-prepared maltose ester was confirmed by Fourier-transform infrared spectra (FTIR), liquid chromatograph–mass spectrum (LC–MS), and scanning electron microscopy (SEM).     

Lipase-catalyzed production of pinolenic acid concentrate from pine nut oil using a recirculating packed bed reactor

Pinolenic acid (PLA) concentrate in fatty acid ethyl ester (FAEE) was efficiently produced from pine nut oil via lipase-catalyzed ethanolysis using a recirculating packed bed reactor (RPBR). The effects of reaction temperature, molar ratio, and residence time on the concentration of PLA were explored. Novozym 435 lipase from Candida antarctica showed less selectivity toward PLA esterified at the sn-3 position when temperature was increased from 45 to 55 °C. For the trials of molar ratio between 1: 50 and 1: 100 (pine nut oil to ethanol), there were no significant differences in the yield of PLA. Residence time of substrate in a RPBR affected significantly the PLA content as well as the yield of PLA. Optimal temperature, molar ratio (pine nut oil to ethanol), and residence time for production of PLA concentrate via lipase-catalyzed ethanolysis in a RPBR were 45 °C, 1: 50, and 3 min, respectively. Under these conditions, the maximal PLA content (36.1 mol%) in the concentrate was obtained during the initial 10 min of reaction.     

有机相脂肪酶催化合成技术在食品及相关领域的应用

对有机相脂肪酶催化合成技术的研究及其在食品、化妆品、医药、精细化工领域的应用进行了综述,表明有机相脂肪酶催化合成技术具有直接利用底物、反应条件温和、反应选择性高、产品容易分离纯化、产品具有绿色环保概念等优点。     

OPTIMIZATION OF LIPASE-CATALYZED ACIDOLYSIS OF SOYBEAN OIL TO PRODUCE STRUCTURED LIPIDS

The condition optimization of lipase-catalyzed acidolysis of soybean oil was conducted by using the response surface methodology (RSM). The results showed that when decision coefficient was 98.34%, the optimal conditions for highest caprylic acid (CA) incorporation was: reaction temperature 35.8C, lipase dosage 11.9% (w/w of substrate), substrate ratio 5.7 (oil/CA, mol/mol), water content 15.4% (w/w of enzyme) and reaction time 20.4 h, and under which conditions, the actually measured incorporation of CA was up to 44.9 mol%, very close to the predicted value 45.7 mol%. This indicates that with RSM, we can effectively optimize the reaction conditions of lipase-catalyzed acidolysis of soybean oil to produce structured lipids.

PRACTICAL APPLICATIONS

In digestion procedure, pancreatic and gastric lipases both have preference for ester bonds located at sn-1 and sn-3 position in triacylglycerols (TGs), and show higher activity towards short- and medium-chain fatty acids (FAs). Dietary TGs are hydrolyzed to sn-2 monoacylglycerols and FAs in the intestine by lipases. Therefore, long-chain polyunsaturated FAs located at sn-2 position may provide sn-2 monoacylglycerols, which are the raw materials in synthesis of TGs in mucosal cells if the dietary fats or oils are MLM- or SLS-type TGs (SLS or MLM are the short-chain or medium-chain FAs located at sn-1 and sn-3 position, while the long-chain FAs are located at sn-2). The short-chain or medium-chain FAs located at sn-1 and sn-3 position are absorbed by the portal vein and rapidly oxidized in the liver as quick source of energy instead of glucose.