脂肪酶催化猪油与辛酸酸解制备功能性脂反应条件的优化

目的:探索有机溶剂体系中酶法酸解猪油与辛酸制备减热量型功能性脂的最佳反应条件。方法:采用响应曲面法中的3水平5因子2星点部分因子试验设计,评价酸解反应中的5个关键因素,即酶量、反应时间、反应温度、底物比率和水分添加量及其交互作用对辛酸插入率的影响,确定最佳反应条件。结果:建立了辛酸插入率对5个变量的一个2次多项式数学模型,该模型极显著(P<0.0001),拟合优度良好。通过主效应分析,得出每个因子对模型的贡献程度从大到小依次为反应温度(负效应)>底物比率>反应时间>酶量(在实验范围内,水分不影响辛酸插入率)。借助模型方程产生的等高线图及统计软件,分析得出最大辛酸插入率下各个因子的最适水平分别为酶量16%,反应时间36h,反应温度50℃,底物比率3.8,水分添加量5%。在此条件下辛酸插入率达到了50.5mol%,与模型预测值50.7mol%非常吻合。结论:应用响应曲面法对有机溶剂体系中酶法酸解猪油与辛酸制备减热量性脂的反应条件进行优化是合理可靠,科学迅速的,且有效的。     

固定化脂肪酶的创制及其在乙酸肉桂酯无溶剂制备中的应用

采用模板法结合辛基(C8)表面修饰制备疏水有序介孔SiO₂载体(OMS-C₈),在此基础上制得固定化脂肪酶(CSL@OMS-C8),成功应用于乙酸肉桂酯的无溶剂酶法制备。利用扫描电镜(SEM)、透射电镜(TEM)、N2-吸附脱附、傅里叶红外(FTIR)对载体材料和固定化酶进行表征。结果显示,OMS具有整齐有序的介孔结构,比表面积达149.9 m2/g,平均孔径为15 nm。经过疏水改性后,接触角从20°提高到120°。优化获得了乙酸肉桂酯的最佳反应条件为温度50℃,肉桂醇与乙酸乙烯酯的摩尔比1∶5,固定化酶添加量2 g/L,反应时间2 h,转化率达到96.6%。催化剂经过5次重复使用肉桂醇的转化率仍能达到80%。     

脂肪酶催化制备生物柴油的研究进展

生物柴油作为一种可再生的清洁能源,以其良好的环境效应受到越来越多的关注。酶法生产生物柴油具有化学催化法不可比拟的优越性,是工业化生产的发展方向。本文综述了利用固定化脂肪酶、游离酶、全细胞生物催化剂制备生物柴油的研究与应用进展,并探讨了我国生物柴油产业化发展的困境和对策。     

改性壳聚糖固定化脂肪酶的研究

以化学改性后的壳聚糖为载体固定假丝酵母99-125脂肪酶,研究了不同的活化剂对壳聚糖表面羟基基团的活化程度,及以活化后壳聚糖为载体采用不同固定化方法对假丝酵母脂肪酶固定效果的影响。结果表明1-乙基-3-(3-甲基氨基)丙基碳二亚胺可有效的活化壳聚糖表面羟基,活化后的壳聚糖表面氨基与戊二醛偶联后形成的壳聚糖为良好的脂肪酶固定化载体,其固定脂肪酶的水解活力可高达86.8U/g。此外,还对影响固定化进程中的各种因素进行了研究,确定最优条件,比较了固定化前后酶的热稳定性、有机溶剂稳定性及最适反应温度。并考察了该固定化脂肪酶催化合成棕榈酸十六酯的操作稳定性,结果表明,连续反应16批之后棕榈酸十六酯的转化率仍能达到85%以上。     

复合脂肪酶催化生物柴油的初步研究

初步探讨了复合脂肪酶催化生物柴油的工艺。优化了复合酶配比条件和叔丁醇反应体系。在无溶剂体系中,Novozym435分别与Lipozyme TLIM和Lipozyme RMIM均以70／30质量比混合时,甲酯得率分别达到94．52％和96．25％,比Novozym435单独催化时的甲酯得率分别提高了9．52％和9．99％。在叔丁醇体系中,当Novozym435与Li-pozyme TLIM和Lipozyme RMIM分别以60／40和80／20的质量比混合时,其甲酯得率分别为85．06％和81．5％,比Novozym435单独催化的效率分别提高了9．89％和7．48％。优化叔丁醇体系中复合酶催化条件后,甲酯得率达92％。     

无溶剂体系脂肪酶动力学拆分2-辛醇及产物的非均相共沸蒸馏提取

为了提高脂肪酶在非水相中对手性仲醇的拆分效率,以2-辛醇为模式底物,建立了以辛酸为酰基供体的无溶剂脂肪酶动力学拆分手性仲醇的反应体系,采用1.5∶1的酸醇摩尔比,45℃条件下反应12 h,2-辛醇的转化率达到49.9%,并且S-2-辛醇的对映体过量率e.e.s=98.2%,反应的对映体比率E600。利用脂肪族仲醇与水形成共沸物的特性,通过非均相共沸蒸馏的方法提取拆分得到的手性仲醇,S-2-辛醇的光学纯度并未降低,并且产率大于90%,产品纯度大于98%。     

有机溶剂中固定化脂肪酶催化硅醇的酯化反应

固定化Mucor miehei脂肪酶可催化有机硅醇和脂肪酸的酯化反应．对固定化酶用量、脂肪酸链长、不同有机硅醇底物、有机溶剂极性和水含量等影响因素进行了初步研究．     

脂肪酶的固定化及棕榈酸抗坏血酸酯的合成研究

讨论了以固定化的黑曲霉脂肪酶为催化剂,以抗坏血酸和棕榈酸甲酯为底物的酯交 换反应及其影响因素.考察了反应温度、维生素C与棕榈酸的摩尔比、反应时间、溶剂的选 择、酶量等因素对催化棕榈酸抗坏血酸酯反应的影响规律.结果表明,摇床转速200r/min、 叔丁醇作溶剂、反应温度为55℃底物棕榈酸甲酯与Vc的摩尔比为2:1、反应时间为28h、脂肪酶浓度为4%,反应转化率为42.1%,产品纯度95%.     

非水介质中脂肪酶催化亚油酸油醇酯合成的研究

利用实验室自制及购买的几种脂肪酶制剂催化的酯化反应来制备亚油酸油醇酯,其中本实验室制备的丝孢酵母脂肪酸酯化效果最好,作为进一步研究的实验用酶。以正己烷为反应溶剂,在微水系统中对影响亚油酸油醉酯合成的各种因素进行了研究,确定酯化反应合成的最适温度为３５℃,０～１００℃反应１０ｈ的酯化率均可达到９０％,最适酯化ｐＨ为８．０,最适底物浓度为０．２５ｍｏｌ／Ｌ,最适水含量为０．０５％,在选用的１１种有机溶剂中,以环己烷的酯化率最高,二甲亚砜最低。     

Acidolysis between Triolein and Short-Chain Fatty Acid by Lipase in Organic Solvents

Ten kinds of lipases were examined as biocatalysts for the incorporation of short-chain fatty acids (acetic, propionic, and butyric acids) into triolein in order to produce one kind of reduced-calorie structured lipids. Trans-esterification (acidolysis) was successfully done in n-hexane by several microbial lipases. Among them, lipase from Aspergillus oryzae was used to investigate the effects of incubation time, substrate molar ratio, and water content on acidolysis. Finally, more than 80% of triolein was incorporated by butyric acid (molar ratio of triolein to butyric acid, 1:10) in the dried n-hexane at 52 °C for 72 h. More than 90% of the products was monosubstituent, which was esterified with this short chain fatty acid at the 1-position of the glycerol moiety of triolein. These results suggest that A. oryzae lipase would be a powerful biocatalyst for the synthesis of low caloric oil, such as triacylglycerol containing a mixture of long- and short-chain aliphatic acids.     

在无溶剂系统中固定化脂肪酶合成聚乙二醇400月桂酸酯

在无溶荆反应系统中,研究了固定化假丝酵母(Candida sp)-1619脂肪酶催化合成聚乙二醇400(PEG400)月桂酸酯的酯化条件。在反应过程中不断脱水和使月桂酸的量高于化学计量值的方法,使酯化率明显提高。分批补加PEG₄₀₀使产量进一步增加。在5．0mmol月桂酸．2．5mmolPEG400,20mg同定化脂肪酶(200u),O．2ml水组成的反应体系中,40℃,锥形瓶敞口振荡反应48h。醑化率达91％;在负压条件下反应．酯化率达98．9％;反应体系中月桂酸的董增加到6．0mmol时,PEG₄₀₀完全被酯化。用己烷提取产物的收率为95％．通过薄层色谱鉴定酯化产物为双酯。     

Continuous interesterification of butteroil and conjugated linoleic acid in a tubular reactor packed with an immobilized lipase

Modified milkfats were produced via interesterification (acidolysis) reactions of butteroil and conjugated linoleic acid (CLA) in a packed bed reactor containing an immobilized lipase preparation from Candida antarctica. The rate expression for the interesterification reaction is of the generalized Michaelis–Menten form. Significant enrichment of butteroil in CLA residues was accomplished at reactor space times (fluid residence times) of 2–4 h at 40–60°C, but the optimum operating temperature was ca. 50°C. Approximately 80–90% of the free CLA fed to the reactor can be converted to its esterified form.     

Optimization of ultrasound-accelerated synthesis of enzymatic octyl hydroxyphenylpropionate by response surface methodology

The ultrasound-accelerated enzymatic synthesis of octyl hydroxyphenylpropionate (OHPP) from p-hydroxyphenylpropionic acid (HPPA) and octanol was investigated in this study. A commercially available immobilized lipase from Candida antarctica, Novozym 435, was used as the biocatalyst. A three-level-three-factor Box-Behnken design experiment and response surface methodology were used to evaluate the effects of temperature, reaction time, and enzyme activity on percent yield of OHPP. The results indicated that temperature and enzyme activity significantly affected percent yield, whereas reaction time did not. A model for the synthesis of OHPP was established. Based on a ridge max analysis, the optimum conditions for OHPP synthesis were predicted to use a reaction temperature of 58.8°C, a reaction time of 14.6 h, and an enzyme activity of 410.5 PLU with a yield of 98.5%. A reaction was performed under these optimal conditions, and a yield of 97.5% ± 0.1% was obtained.     

脂肪酶合成聚乙二醇400油酸单酯和双酯的影响因素

研究了固定化假丝酵母（Ｃａｎｄｉｄａｓｐ．）１６１９脂肪酶合成聚乙二醇４００油酸单酯与双酯的影响因素。不同摩尔比的底物反应６ｈ都有单酯和双酯生成。酸与醇的摩尔比为０２５∶１到２∶１时,生成单酯与双酯的比例在３５∶１到４∶１的范围内;当酸与醇的摩尔比达到３∶１至８∶１时,单、双酯的生成量相仿。反应达平衡时（２４ｈ）,不同摩尔比底物的反应产物都是双酯。在含己烷的反应体系中,反应平衡时有单酯存在,摩尔比为２∶１时,反应物中单、双酯比达到１∶３２。     

Lipase-catalyzed acidolysis of menhaden oil with conjugated linoleic acid: effect of water content

The effect of the water content on the lipase-catalyzed (Candida rugosa) interesterification (acidolysis) of menhaden oil with conjugated linoleic acid was studied for amounts of added water ranging from 0-4% (w/w). The rate of the acidolysis reaction increased with increasing water content, but the corresponding percentage of n-3 fatty acids liberated also increased. The implications of water content for minimization of the release of n-3 fatty acid residues while maximizing incorporation of CLA are discussed.     

有机介质中脂肪酶催化合成亚麻酸甘油酯

研究固定化脂肪酶在有机溶剂中催化亚麻酸甘油酯的合成反应。考察了有机溶剂、酯化温度、物料比、催化剂用量、酯化时间等因素对酯化率的影响。结果表明:以正己烷为溶剂、酯化温度60℃、酸醇摩尔比1:2.5条件下、反应24h,亚麻酸甘油酯化率为90%以上。