柴油溶剂中脂肪酶催化高酸值废油脂酯化制备生物柴油

采用0＃柴油作为反应溶剂,利用固定化脂肪酶催化高酸值废油脂与甲醇酯化反应制备生物柴油。来源于Candida antarctica的固定化脂肪酶Novozym435在0＃柴油溶剂中具有极高的催化活性。以酸价高达157×10-3的废油脂为原料,废油脂质量比10%的Novozym435,甲醇与废油脂初始摩尔比2∶1,0＃柴油与废油脂质量比5∶1,摇床摇速170r/min,50℃下反应2h甲酯化率可达95.10%。0＃柴油作为反应溶剂有效地溶解了高酸值废油脂和甲醇,降低了反应体系的黏度和消除了甲醇对Novozym435的负面影响,提高了Novozym435的稳定性。同时,0＃柴油溶剂对未脱胶废油脂中残留的对脂肪酶有害的磷脂等胶类物质具有一定的稀释作用。该工艺省却了溶剂蒸馏的繁琐工序,直接得到脂肪酸甲酯和石化柴油的混合燃料。     

有机相中脂肪酶催化合成乳酸乙酯

 考察了在双底物抑制下脂肪酶催化合成乳酸乙酯,最佳溶剂为叔丁醇,在所选的几种脂肪酶中,固定化于大孔丙烯酸树脂的南极假丝酵母脂肪酶B (Novozym 435)的催化活性最好. 对反应条件进行了优化,当酸醇摩尔比为1∶8, 反应温度60 ℃, 酸浓度0.3 mol/L, 酶浓度45 g/mol, 摇床转速200 r/min时产率达到77%, 脂肪酶Novozym 435重复使用6次后产率仍然可达到60%.     

脂肪酶催化扁桃酸乙酯酯交换反应的研究

利用脂肪酶Novozym 435在正丁醇体系中催化酯交换反应,对(R,S)-扁桃酸乙酯进行了动力学拆分,考察了系统初始加水量,反应温度,振荡速度,底物浓度等因素对脂肪酶催化活性和对映体选择性的影响.研究结果表明,最适初始加水量为0.4%;在20℃~60℃范围内,酶催化活性随温度升高而增加,酶选择性随温度先升高后下降,最适温度45℃;底物扁桃酸乙酯浓度达5000 mmol/L时,未观察到底物抑制现象,反应初速度为2.78mmol.L-1.m in-1.     

脂肪酶催化二次动力学拆分制备高光学纯度(S)-萘普生

设计了一种利用立体选择性相反的两种脂肪酶催化二次动力学拆分,由外消旋萘普生甲酯制备高光学纯度(S)-萘普生的方法。理论曲线预测,与简单的酶促动力学拆分反应相比,二次动力学拆分可以明显提高高光学纯度产物的产率.根据几种脂肪酶在微水/异辛烷双液相反应体系中不对称水解萘普生甲酯的立体选择性和对映体比率(E),首先选用R选择性的固定化南极假丝酵母脂肪酶(Novozym 435)对外消旋萘普生甲酯进行第一次拆分,然后选用S选择性的柱状假丝酵母脂肪酶(CRL)对S过量的剩余底物萘普生甲酯在同样的反应体系中进行第二次拆分.该二次拆分反应对映体过量值为96.8%的(S)-萘普生产率达19.9%.     

脂肪酶催化外消旋对羟基苯甘氨酸甲酯水解制备对映体纯D-对羟基苯甘氨酸的新方法

 基于在反应体系中添加碳酸氢铵可有效地促进酶促外消旋对羟基苯甘氨酸甲酯不对称水解这一有趣现象的发现,探讨了利用有机介质中酶促外消旋对羟基苯甘氨酸甲酯不对称水解制备对映体纯D-对羟基苯甘氨酸及其衍生物的可能性,研究了不同来源的酶、摇床转速、水含量、对羟基苯甘氨酸甲酯浓度、反应介质及温度等因素对该反应的影响. 结果表明,在所研究的11种酶中脂肪酶Novozym 435对该反应的催化活性和对映体选择性较高,叔丁醇为最合适的反应介质,最适水含量为0.4%(V/V),对羟基苯甘氨酸甲酯的适宜浓度为20 mmol/L,最适摇床转速和反应温度分别为130 r/min和30 ℃. 在此优化条件下反应26 h后,底物转化率和产物ee分别为39.8%和95.2%.     

无溶剂系统中固定化脂肪酶催化废油脂转酯生产生物柴油

 探讨了无溶剂系统中固定化脂肪酶Novozym 435催化餐饮业废油脂转酯生产生物柴油. 反应副产物甘油可吸附在固定化酶载体表面,采用丙酮洗涤除去甘油可提高酶的稳定性. 适宜的醇/油摩尔比、酶用量、反应温度和摇床转速分别为1, 6.6 U/g, 35～40 ℃和150 r/min,不宜加水到反应体系中. 采用分步加入甲醇的方式可减轻甲醇对酶的毒害作用. 分别在反应进行到6和14 h时用丙酮除去酶表面的甘油,然后按醇/油摩尔比为1的比例加入甲醇继续反应,反应30 h后产物中的脂肪酸甲酯含量为88.6%. 连续反应300 h后,酶活性基本没有下降.     

游离脂肪酶NS81006催化油脂醇解制备生物柴油的酶促反应动力学

探究了游离脂肪酶NS81006催化油脂甲(乙)醇解制备生物柴油的反应历程,并对该体系进行了酶促反应动力学研究.结果表明,催化过程中油脂同时存在酯交换及先水解再酯化两种反应历程.在以甲醇或乙醇作为酰基受体的反应过程中,酯交换反应速率明显大于水解反应速率.进一步研究表明,油脂甲醇解反应速率常数大于乙醇解,揭示了以甲醇或乙醇为不同酰基受体时反应速率存在差异的主要原因在于乙醇解反应的酯交换过程较慢.     

非水介质中曲克芦丁乙烯酯的酶促合成

在非水介质中,选择性催化曲克芦丁羟乙基上的伯羟基发生酯交换反应,合成一系列曲克芦丁乙烯酯.同时考察了酶源、酶量、反应介质、酰化试剂链长、溶剂含水量、反应时间等因素对曲克芦丁酶促酯交换反应区域选择性的影响.结果表明:以吡啶为溶剂,其含水量1%时,枯草杆菌碱性蛋白酶催化活性最高,随着酰基供体碳链的减少,产率增大,且反应达平衡的时间缩短.     

废茶油的精制及其合成生物柴油的研究

本文以废茶油为原料,经过脱胶脱酸等预处理后与甲醇进行酯交换反应制取生物柴油.探讨了反应时间、反应温度、醇-油摩尔比和催化剂用量等因素对废茶油-甲醇酯交换反应的影响,并且采用正交实验优化合成条件,确定了反应的最佳操作条件以及影响反应的关键因素.研究结果表明,酯交换反应进行的最佳反应条件为:醇油摩尔比为25:1、催化剂用量为油重的1.0%、反应时间为30min、反应温度为60℃,茶油酸甲酯产率77.34%.     

猪胰脂肪酶催化外消旋P-手性α-羟基磷酸酯类化合物的动力学拆分（英文）

酶催化具有高效、高选择性以及反应条件温和等优点,已经成为有机合成领域的重要方法.研究了P-手性α-羟基磷(膦)酸酯类化合物的合成方法.在猪胰脂肪酶的催化作用下,外消旋α-羟基磷(膦)酸酯与乙酸乙烯酯之间能够顺利地发生酯交换反应,以高达49%的产率和83%的ee值得到相应的手性产物,且该反应在非常温和的条件下就能够进行.同时,在计算机的辅助下建立了酶-底物之间的结合模型,通过对接的方法揭示了反应中酶催化对映选择性的机理.     

Lipase-Catalyzed Transesterification of Rapeseed Oil for Biodiesel Production with tert-Butanol

Biodiesel is a fatty acid alkyl ester that can be derived from any vegetable oil or animal fat via the process of transesterification. It is a renewable, biodegradable, and nontoxic fuel. In this paper, we have evaluated the efficacy of a transesterification process for rapeseed oil with methanol in the presence of an enzyme and tert-butanol, which is added to ameliorate the negative effects associated with excess methanol. The application of Novozym 435 was determined to catalyze the transesterification process, and a conversion of 76.1% was achieved under selected conditions (reaction temperature 40 °C, methanol/oil molar ratio 3:1, 5% (w/w) Novozym 435 based on the oil weight, water content 1% (w/w), and reaction time of 24h). It has also been determined that rapeseed oil can be converted to fatty acid methyl ester using this system, and the results of this study contribute to the body of basic data relevant to the development of continuous enzymatic processes.     

Enzyme catalyzed production of biodiesel from olive oil

Biodiesel (fatty acid methyl esters) was produced by transesterification of triglycerides (triolein) present in olive oil with methanol and Novozym435. The effect of the molar ratio of methanol to triolein, semibatch (stepwise addition of methanol) vs batch operation, enzyme activity, and reaction temperature on overall conversion was determined. Stepwise methanolysis with a 3:1 methanol to triolein molar ratio and an overall ratio of 8:1 gave the best results. The final conversion and yield of biodiesel were unaffected by initial enzyme concentrations greater than 500 U/mL olive oil. The optimum reaction temperature was 60 degrees C. Comparison of conversion data between a test-tube scale reactor and a 2-L batch reactor revealed that the difference in conversion was within 10%. Experiments were also carried out with used cooking oil; the conversion with used cooking oil was slightly lower but no major differences were observed. The efficacy of Novozym435 was determined by reusing the enzyme; although the enzyme's relative activity decreased with reuse, it still retained 95% of its activity after five batches and more than 70% after as many as eight batches.     

Optimization of lipase-catalyzed transesterification of lard for biodiesel production using response surface methodology

Biodiesel, an alternative diesel fuel made from renewable biological resources, has become more and more attractive recently. Combined use of two immobilized lipases with complementary position specificity instead of one lipase is a potential way to significantly reduce cost of lipase-catalyzed biodiesel production. In this study, the process of biodiesel production from lard catalyzed by the combined use of Novozym435 (non-specific) and Lipozyme TLIM (1,3-specific) was optimized by response surface methodology. The optimal reaction conditions were 0.04 of amount of lipase/oil (w/w), 0.49 of proportion of Novozym435/total lipases (w/w), 0.55 of quantity of tert-butanol/oil (v/v), 5.12 of quantity of methanol/oil (mol/mol), and 20 h of reaction time, by which 97.2% of methyl ester (ME) yield was attained, very close to the predicted value (97.6%). This optimal reaction condition could be true of other similar reactions with plant and animal oil resources; their ME yield could be higher than 95%. The lipases regenerated by washing with organic solvent after each reaction cycle could be continuously reused for 20 cycles without any loss of activity, exhibiting very high manipulation stability.     

Combining Enzymatic Esterification with Conventional Alkaline Transesterification in an Integrated Biodiesel Process

An integrated biodiesel process that combines enzymatic esterification and alkaline transesterification is suggested. With focus on the enzymatic step, the paper provides proof of concept and suggestions for further process development. Hence, palm fatty acid distillate (PFAD) has been enzymatically converted to fatty acid methyl esters in a two-step process using the immobilized lipase Novozym 435 in packed-bed columns. With only a small excess of methanol, the first reaction stage could reduce the free fatty acid (FFA) content from 85% to 5%. After removal of water by simple phase separation, it was possible to lower the FFA content to 2.5% in a second reaction stage. Both reaction stages are relatively fast with suggested reaction times of 15 min in column 1 (productivity 10 kg/kg/h) and 30 min in column 2 (productivity 5 kg/kg/h), resulting in 15% FFA after column 1 and 5% FFA after column 2. A lifetime study indicated that approximately 3,500 kg PFAD/kg Novozym 435 can be treated in the first reaction stage before the enzyme has become fully inactivated. With further optimization, the enzymatic process could be a real alternative to today’s sulfuric acid catalyzed process.     

无溶剂体系脂肪酶催化合成阿魏酸油醇酯

对无溶剂体系中阿魏酸的转酯化疏水改性进行了研究,确立了减压反应器(0.001 MPa)中Novozym 435脂肪酶催化阿魏酸乙酯和油醇进行转酯化反应合成新型抗氧化剂阿魏酸油醇酯的方法.发现水活度(aw)明显影响转酯反应,阿魏酸油醇酯产率在aw＜0.01-0.75范围内随着水活度的增加而降低,推测底物阿魏酸乙酯和产物阿...     

Comparison and optimisation of biodiesel production from <Emphasis Type="Italic">Jatropha curcas</Emphasis> oil using supercritical methyl acetate and methanol

In this study, biodiesel has been successfully produced by transesterification using non-catalytic supercritical methanol and methyl acetate. The variables studied, such as reaction time, reaction temperature and molar ratio of methanol or methyl acetate to oil, were optimised to obtain the optimum yield of fatty acid methyl ester (FAME). Subsequently, the results for both reactions were analysed and compared via Response Surface Methodology (RSM) analysis. The mathematical models for both reactions were found to be adequate to predict the optimum yield of biodiesel. The results from the optimisation studies showed that a yield of 89.4 % was achieved for the reaction with supercritical methanol within the reaction time of 27 min, reaction temperature of 358°C, and methanol-to-oil molar ratio of 44. For the reaction in the presence of supercritical methyl acetate, the optimum conditions were found to be: reaction time of 32 min, reaction temperature of 400°C, and methyl acetate-to-oil molar ratio of 50 to achieve 71.9 % biodiesel yield. The differences in the behaviour of methanol and methyl acetate in the transesterification reaction are largely due to the difference in reactivity and mutual solubility of Jatropha curcas oil and methanol/methyl acetate.     

华根霉全细胞脂肪酶催化合成生物柴油

比较了5种不同商品化脂肪酶和自制的华根霉CCTCCM201021全细胞脂肪酶(RCL)催化油脂合成生物柴油的转化效果,结果表明,RCL能有效应用于无溶剂体系催化合成生物柴油.在无溶剂体系中对该酶催化生物柴油的转酯化反应工艺进行优化,考察了甲醇用量、体系含水量、酶的添加量和反应温度对生物柴油收率的影响,使生物柴油最终收率大于86.0%.在有机溶剂体系中选择不同有机溶剂作为助溶剂进行转酯化反应,发现logP值在4.0～4.5的有机溶剂具有较好的转化效果.其中以正庚烷为助溶剂的转酯化反应具有最高的生物柴油收率86.7%.在无溶剂体系中RCL催化转化油酸和模拟高酸价油脂合成脂肪酸甲酯的研究表明,该酶具有很好的催化合成生物柴油的潜力.     

New eutectic ionic liquids for lipase activation and enzymatic preparation of biodiesel

The enzymatic preparation of biodiesel has been hampered by the lack of suitable solvents with desirable properties such as high lipase compatibility, low cost, low viscosity, high biodegradability, and ease of product separation. Recent interest in using ionic liquids (ILs) as advanced reaction media has led to fast reaction rates and high yields in the enzymatic synthesis of biodiesel. However, conventional (i.e., cation-anion paired) ILs based on imidazolium and other quaternary ammonium salts remain too expensive for wide application at industrial scales. In this study, we report on newly-synthesized eutectic ILs derived from choline acetate or choline chloride coupled with biocompatible hydrogen-bond donors, such as glycerol. These eutectic solvents have favorable properties including low viscosity, high biodegradability, and excellent compatibility with Novozym(?) 435, a commercial immobilized Candida antarctica lipase B. Furthermore, in a model biodiesel synthesis system, we demonstrate high reaction rates for the enzymatic transesterification of Miglyol(?) oil 812 with methanol, catalyzed by Novozym(?) 435 in choline acetate/glycerol (1:1.5 molar ratio). The high conversion (97%) of the triglyceride obtained within 3 h, under optimal conditions, suggests that these novel eutectic solvents warrant further exploration as potential media in the enzymatic production of biodiesel.     

Clean synthesis of biodiesel over solid acid catalysts of sulfonated mesopolymers

FDU-15-SO₃H, a solid acid material prepared from the sulfonation of FDU-15 mesoporous polymer, has been demonstrated to serve as an efficient catalyst in the esterification of palmitic acid with methanol as well as in the transesterification of fatty acid-edible oil mixture. FDU-15-SO₃H achieved an acid conversion of 99.0% when the esterification was carried out at 343 K with a methanol/palmitic acid molar ratio of 6:1 and 5 wt% catalyst loading. It was capable of giving 99.0% yield of fatty acid methyl esters (FAME) when the transesterification of soybean oil was performed at 413 K and the methanol/oil weight ratio of 1:1. FDU-15-SO₃H was further applied to the transesterification/esterification of the oil mixtures with a varying ratio of soybean oil to palmitic acid, which simulated the feedstock with a high content of free fatty acids. The yield of FAME reached 95% for the oil mixtures containing 30 wt% palmitic acid. This indicated the sulfonated mesopolymer was a potential catalyst for clean synthesis of fuel alternative of biodiesel from the waste oil without further purification.     

Addition of an azido group to epoxidised fatty acid methyl esters of Jatropha curcas by epoxy cleavage

Azidohydrin was synthesized from the seed oil of Jatropha curcas by use of simple chemical reactions. This entailed first, transesterification of the seed oil of J. curcas to produce the fatty acid methyl esters, epoxidation of the fatty acid methyl esters to form the epoxides, then azidation of the epoxidised fatty acid methyl esters. The yield of the azidation reaction was 93.60 %, and the distribution of azide and alcohol functionality on the fatty acid was approximately random. The reactants and products were monitored and confirmed by FTIR and NMR spectroscopy.