Lipozyme TL IM催化油酸酯化反应制备1,3-甘油二酯

探究了固定化脂肪酶Lipozyme TL IM催化单甘酯与油酸进行酯化反应制备1,3-甘油二酯的可能性,考察了溶剂、水活度、反应温度、底物摩尔比以及溶剂用量对甘油二酯产率及脂肪酶1,3-位置选择性的影响.在优化的实验条件(45℃,1.5 g Lipozyme TL IM,油酸与单甘酯摩尔比1.5∶1,6.0 g三氯甲烷,水活度为0.33)下,反应6 h时,甘油二酯产率可达80%,其中1,3-甘油二酯产率高达92%以上.Lipozyme TL IM循环使用5次后,甘油二酯产率及脂肪酶选择性无明显下降.     

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.     

固定化脂肪酶催化麻疯树油与碳酸二甲酯制备生物柴油的研究

以介孔硅材料(MPS)为载体将脂肪酶固定化,以碳酸二甲酯为酰基受体,对固定化酶催化碳酸二甲酯进行了反应路径(原料油)、反应条件(反应温度、碳酸二甲酯的用量、加水量)的优化,在最佳的条件下对实验过程中所用的固定化酶进行重复使用性的考察。实验结果表明,不同种油与碳酸二甲酯反应在固定化酶的催化下制备生物柴油的产率以麻疯树油为最高,最佳反应条件是碳酸二甲酯的浓度为16m L/g、不加水,在50℃下反应24h,生物柴油得率达81.6%。     

固定化脂肪酶催化碳酸二甲酯制备生物柴油的研究

以介孔硅材料(MPS)为载体将脂肪酶固定化,以碳酸二甲酯为酰基受体,对固定化酶催化碳酸二甲酯进行了反应路径(原料油)、反应条件(反应温度、碳酸二甲酯的用量、加水量)的优化,在最佳的条件下对实验过程中所用的固定化酶进行重复使用性的考察.实验结果表明,不同种油与碳酸二甲酯反应在同定化酶的催化下制备生物柴油的产率以麻疯树油为最高,最佳反应条件是碳酸二甲酯的浓度为16mL/g、不加水,在50℃下反应24h,生物柴油得率达81.6％.     

紫外分光光度法表征Lipozyme TL IM脂肪酶转酯化活性

建立了一种新的有机相脂肪酶转酯化活性测定方法. 以正己烷为溶剂,脂肪酶催化棕榈酸对硝基苯酯和正丁醇的转酯化反应为模型反应,通过测定反应液中310 nm下吸光值的变化计算反应转化率. 以气相色谱法对新建的紫外分光光度法进行验证,分别采用这两种方法测定了七种商品化脂肪酶的转酯化活性,两种方法所得实验结果基本一致. 利用紫外分光光度检测法考察了Lipozyme TL IM脂肪酶催化转酯化的时间进程及合成活性与酶量的关系,并对Lipozyme TL IM催化转酯化的性质（最适溶剂、酰基受体特异性、醇耐受性、最优反应温度和热力学稳定性）进行了表征.     

固定化脂肪酶催化合成生物柴油

固定化脂肪酶催化合成生物柴油;转酯反应;固定化脂肪酶;菜籽油;甲醇;生物柴油     

固定化扩展青霉脂肪酶的制备及其在玉米油转酯反应中的应用

采用吸附法对来源于扩展青霉Penicillium expansum的脂肪酶进行了固定化.从20种不同来源的树脂中筛选出固定化效率高且价格低廉的D4020树脂作为载体,系统研究了固定化条件对固定化效率及固定化酶转酯活力的影响.结果表明,最适加酶量、缓冲液pH和吸附时间分别为0.7 g/g、9.4和4 h.冻干时添加0.5%的半乳糖有助于提高固定化酶的转酯活力.在上述优化条件下,固定化酶的转酯活力为404.0 U/g,而所用的游离酶不能催化该转酯反应.利用该固定化酶催化玉米油转酯反应生产生物柴油时,叔戊醇为适宜的反应介质,其最适添加量为0.5 ml/g;适宜的酶量、加水量和反应温度分别为60.6 U/g、油重的1.2%和35℃.按醇/油摩尔比为1的比例分别在反应0、2和6 h时加入甲醇,在优化反应条件下,反应24 h后甲酯产率达85.0%;固定化脂肪酶具有较好的操作稳定性,反应10批次时,相对酶活力为62.8%.     

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.     

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%.     

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。     

Enzymatic Synthesis of Biodiesel via Alcoholysis of Palm Oil

The enzymatic alcoholysis of crude palm oil with methanol and ethanol was investigated using commercial immobilized lipases (Lipozyme RM IM, Lipozyme TL IM). The effect of alcohol (methanol or ethanol), molar ratio of alcohol to crude palm oil, and temperature on biodiesel production was determined. The best ethyl ester yield was about 25 wt.% and was obtained with ethanol/oil molar ratio of 3.0, temperature of 50 °C, enzyme concentration of 3.0 wt.%, and stepwise addition of the alcohol after 4 h of reaction. Experiments with 1 and 3 wt.% of KOH and 3 wt.% of MgO were carried out to compare their catalytic behavior with the enzymatic transesterification results. The commercial immobilized lipase, Lipozyme TL IM, showed the best catalytic performance.     

Enzymatic Biodiesel Synthesis in Semi-Pilot Continuous Process in Near-Critical Carbon Dioxide

A semi-pilot continuous process (SPCP) for enzymatic biodiesel synthesis utilizing near-critical carbon dioxide (NcCO₂) as the reaction medium was developed with the aim of reducing the reaction time and alleviating the catalyst inhibition by methanol. Biodiesel synthesis was evaluated in both lab-scale and semi-pilot scale reactors (batch and continuous reactors). In a SPCP, the highest conversion (～99.9 %) in four and a half hours was observed when three-step substrate (methanol) addition (molar ratio [oil/methanol]?=?1:1.3) was used and the reaction mixture containing enzyme (Lipozyme TL IM, 20 wt.% of oil) was continuously mixed (agitation speed?=?300 rpm) at 30 °C and 100 bar in a CO₂ environment. The biodiesel produced from canola oil conformed to the fuel standard (EU) even without additional downstream processing, other than glycerol separation and drying.     

Biodiesel fuel production by the transesterification reaction of soybean oil using immobilized lipase

The enzymatic alcoholysis of soybean oil with methanol and ethanol was investigated using a commercial, immobilized lipase (Lipozyme RMIM). The effect of alcohol (methanol or ethanol), enzyme concentration, molar ratio of alcohol to soybean oil, solvent, and temperature on biodiesel production was determined. The best conditions were obtained in a solvent-free system with ethanol/oil molar ratio of 3.0, temperature of 50 degrees C, and enzyme concentration of 7.0% (w/w). Three-step batch ethanolysis was most effective for the production of biodiesel. Ethyl esters yield was about 60% after 4 h of reaction.     

Monitoring lipase-catalyzed methanolysis of sunflower oil by reversed-phase high-performance liquid chromatography: elucidation of the mechanisms of lipases

Reversed-phase high-performance liquid chromatography (RP-HPLC) with UV detection at 210 nm was used to monitor the formation of the major compounds during the lipase-catalyzed transesterification reaction of sunflower oil with methanol. Individual triacylglycerols, diacylglycerols, monoacylglycerols as well as fatty acids and their corresponding methyl esters were separated using acetonitrile/acetone as a mobile phase and a combined linear gradient-isocratic-step gradient-isocratic elution procedure. Another relatively short method consisting of a linear gradient elution followed by an isocratic elution gave similar results, yet with lower resolution. HPLC/mass spectrometry with an ion trap analyzer and atmospheric pressure chemical ionization source was used for the identification of the individual compounds. Individual calibration curves obtained with UV detection at 210 nm were found to be of use for quantitative analyses of double-bond containing methyl esters and acylglycerols. The use of the RP-HPLC methods in the elucidation of the mechanisms of three immobilized lipases, namely Lipozyme TL IM, Lipozyme RM IM and Novozym 435, in biodiesel production was described.     

CaO-MgO@CoFe_2O_4磁性固体碱的制备及其大豆油酯交换反应催化性能

以草酸盐为前驱体采用两步法制备了一种以CaO-MgO作为活性组分,以CoFe_2O_4作为磁核的磁性固体碱催化剂,并用于大豆油与甲醇的酯交换反应合成生物柴油。对制备的磁性固体碱催化剂进行了磁滞回线、X-射线衍射(XRD)、CO_2-TPD及透射电镜(TEM)表征。考察了不同核壳物质的量比、焙烧温度、反应温度、反应时间、醇油物质的量比以及催化剂用量等因素对大豆油转化为生物柴油产率的影响。结果表明,采用核壳物质的量比为1∶6、焙烧温度为700℃所制备的CaO-MgO@CoFe_2O_4催化剂,当醇油物质的量比为12、催化剂用量为大豆油质量的1.0%时,在65℃下反应时间3 h,生物柴油收率高达97.1%。该催化剂具有较好的重复利用性能,重复利用四次后生物柴油的收率仍可达90%。     

Biodiesel Production from Various Oils Under Supercritical Fluid Conditions by Candida antartica Lipase B Using a Stepwise Reaction Method

In this study, we evaluate the effects of various reaction factors, including pressure, temperature, agitation speed, enzyme concentration, and water content to increase biodiesel production. In addition, biodiesel was produced from various oils to establish the optimal enzymatic process of biodiesel production. Optimal conditions were determined to be as follows: pressure 130 bar, temperature 45 °C, agitation speed 200 rpm, enzyme concentration 20%, and water contents 10%. Among the various oils used for production, olive oil showed the highest yield (65.18%) upon transesterification. However, when biodiesel was produced using a batch system, biodiesel conversion yield was not increased over 65%; therefore, a stepwise reaction was conducted to increase biodiesel production. When a reaction medium with an initial concentration of methanol of 60 mmol was used and adjusted to maintain this concentration of methanol every 1.5 h during biodiesel production, the conversion yield of biodiesel was 98.92% at 6 h. Finally, reusability was evaluated using immobilized lipase to determine if this method was applicable for industrial biodiesel production. When biodiesel was produced repeatedly, the conversion rate was maintained at over 85% after eight reuses.     

Application of a Chitosan-Immobilized Talaromyces thermophilus Lipase to a Batch Biodiesel Production from Waste Frying Oils

Waste frying oil, which not only harms people’s health but also causes environmental pollution, can be a good alternative to partially substitute petroleum diesel through transesterification reaction. This oil contained 8.8 % of free fatty acids, which cause a problem in a base-catalyzed process. In this study, synthesis of biodiesel was efficiently catalyzed by the covalently immobilized Talaromyces thermophilus lipase and allowed bioconversion yield up to 92 % after 24 h of reaction time. The optimal molar ratio was four to six parts of methanol to one part of oil with a biocatalyst loaded of 25 wt.% of oil. Further, experiments revealed that T. thermophilus lipase, immobilized by a multipoint covalent liaison onto activated chitosan via a short spacer (glutaraldehyde), was sufficiently tolerant to methanol. In fact, using the stepwise addition of methanol, no significant difference was observed from the one-step whole addition at the start of reaction. The batch biodiesel synthesis was performed in a fixed bed reactor with a lipase loaded of 10 g. The bioconversion yield of 98 % was attained after a 5-h reaction time. The bioreactor was operated successfully for almost 150 h without any changes in the initial conversion yield. Most of the chemical and physical properties of the produced biodiesel meet the European and USA standard specifications of biodiesel fuels.     

酸化油固定床酶法合成生物柴油研究

酸化油是油脂工作中以皂脚、油脚经酸化处理得到的产品.它的主要成份是游离脂肪酸及中性油,是生产脂肪酸的重要原料,但生产过程中有水解废水的产生,若将其直接排放,既污染了环境又浪费了资源.     

原位共沉淀法制备NiMg(Al)O/γ-Al2O3催化剂及其酯交换性能

以γ-Al₂O₃为载体通过原位共沉淀法制备NiMgAl-LDHs/γ-Al₂O₃,经焙烧后得到NiMg（Al）O/γ-Al₂O₃催化剂,通过TG-DTG、XRD、SEM、BET、FT-IR、CO₂-TPD等手段对催化剂进行了表征,并对其在酯交换制备生物柴油反应中的催化性能进行了研究。结果表明,NiMgAl-LDHs和NiMg（Al）O成功在γ-Al₂O₃内孔表面生长,并有良好的结合度。催化剂对酯交换具有很高的催化活性;在醇油物质的量比为12：1的条件下反应3 h,生物柴油产率为95%,重复使用七次后,生物柴油产率仍然在82%以上。     

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.