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1.
脂肪酶协同催化猪油合成生物柴油工艺研究   总被引:1,自引:0,他引:1       下载免费PDF全文
探讨了以乙酸甲酯为酰基受体两种脂肪酶协同催化猪油转酯合成生物柴油的工艺条件。首先利用单因子试验确定2种固定化脂肪酶Novozym435、Lipozyme TLIM单独作为催化剂时的最佳酶用量为40%,反应温度为50℃,乙酸甲酯用量为14(相对于油的摩尔比)。在此基础上,采用3因素5水平和3个中心点的中心组分旋转设计法研究了上述2种脂肪酶协同使用时脂肪酶用量(g/g)、混合酶的配比(%/%)以及乙酸甲酯用量诸因素共同作用对转酯反应转化率的影响。优化后的反应条件为:总酶用量为40%,混合酶配比为50/50,乙酸甲酯用量为14,在该条件下甲酯得率可达97.6%,比同质量的Novozym435、Lipozyme TLIM的催化活性分别高出7.6%、22.3%。表明脂肪酶协同催化猪油合成生物柴油工艺可以较好地提高甲酯得率,并且节约生产成本。  相似文献   

2.
复合脂肪酶催化生物柴油的初步研究   总被引:6,自引:0,他引:6  
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%。  相似文献   

3.
以叔丁醇为反应体系,研究固定化Novozym 435 和Lipozyme TLIM 脂肪酶协同催化餐饮废油合成生物柴油.采用5 因素5 水平响应面法优化工艺参数,最佳工艺条件为:复合酶用量4%( wt.)、复合酶配比1:1(w/w),油/醇摩尔比1:5,反应温度50℃,叔丁醇用量50%(油体积比v/v).在此条件下反应10 h,生物柴油转化率为83.65 %.复合酶操作稳定性较高,重复使用10 个批次,生物柴油转化率仍保持在80% 以上.  相似文献   

4.
研究了不同因素对制备固定化荧光假单胞菌脂肪酶的影响及固定化酶的酶学性质,并初步探讨了利用该固定化酶制备生物柴油的工艺。以海藻酸钠明胶为复合载体,采用包埋法制备固定化荧光假单胞菌脂肪酶,考察了载酶量、颗粒直径等因子对固定化效果的影响,并用制备的固定化酶进行了酶促酯交换合成生物柴油的工艺研究,考察了反应条件如酶量、反应温度、甲醇流加方式、醇油比等因素对甲酯得率的影响。试验结果表明,制备固定化荧光假单胞菌脂肪酶的最优条件为:每克载体给酶量为300 IU,选用6号注射器针头(内径为0.5 mm);通过酯交换,催化大豆油合成生物柴油的最佳反应工艺参数为:固定化酶25%,醇油比4:1,含水量6%,反应温度40℃;此条件下反应35 h后,甲酯的最高得率可达82%。  相似文献   

5.
采用固定化脂肪酶催化花椒籽皮油制备生物柴油,研究了该转酯化反应的工艺条件.结果表明:在脂肪酶用量25%(质量分数).含水量10%(质量分数),正己烷用量15%(质量分数).醇油比3:1.分三次添加甲醇,于反应温度45℃下反应时间24 h,固定化脂肪酶使花椒籽皮油的棕榈酸甲酯的转化率达到82.5%.  相似文献   

6.
从4种不同来源的脂肪酶,2种不同来源的蛋白酶中筛选出了具有较高活性和对映体选择性的能催化乙酸甲基苯甲酯氨解反应的脂肪酶Novozym 435。进一步探讨了氨源、酶浓度、底物等因素对该酶反应的影响。结果表明,在优化条件下,氨解反应6h,转化率为51.6%,残留底物中(-)-乙酸甲基苯甲酯对映体过剩值可达99%以上。  相似文献   

7.
系统研究了反应介质、水活度、温度、pH等因素对脂肪酶Novozym435催化乙酸甲基苯甲酯立体选择性氨解反应的影响。以正己烷为反应介质,酶表现出较高的催化活性和对映体选择性;适宜的反应温度为25℃~35℃;最适反应体系初始水活度为0.33;较适宜的pH范围为6~7。  相似文献   

8.
【目的】探讨复合酶协同催化体系在含水量较高的体系中催化油脂制备生物柴油的工艺条件。【方法】通过基因工程手段在毕赤酵母中分别高效分泌表达南极假丝酵母脂肪酶(CALB)和米根霉脂肪酶(ROL),构建CALB和ROL复合酶协同催化体系制备生物柴油,利用单因素实验优化工艺条件,以甲酯化得率作为复合酶协同催化体系效能的评价标准。【结果】优化工艺条件为:CALB?ROL最佳复合酶配比为7?3,每克大豆油中加入16 U的复合脂肪酶,甲醇与大豆油摩尔比为4?1,并按0 h时2?1醇油摩尔比,12 h和24 h时以1?1醇油摩尔比分批加入甲醇,含水量为30%-60%之间,40°C反应29-34 h,甲酯得率达到93%。【结论】该复合酶协同催化体系对环境友好,与常规酶法制备生物柴油工艺相比对酶的使用量和催化时间减少幅度都在50%以上,本复合酶协同催化体系能有效降低生物柴油制备成本,具有较好的工业化应用前景。  相似文献   

9.
超声波辅助下脂肪酶催化高酸值废油脂制备生物柴油   总被引:3,自引:0,他引:3  
探讨了超声波辅助条件下脂肪酶催化高酸值废油脂转化为生物柴油的反应。来源于Aspergillus oryzae和Candida antarctica的固定化脂肪酶,在超声波辅助下,对高酸值废油脂转化为生物柴油具有高的催化活性。以来自于C.antarctica的固定化脂肪酶Novozym435为催化剂,以酸价为157mg KOH/g的高酸值废油脂为原料在超声波辅助下与丙醇反应,在脂肪酶用量为油质量的8%、初始醇油摩尔比为3∶1、反应温度控制在40~45℃、超声波频率和功率分别采用28kHz和100W的条件下,反应50min转化率达到94.86%。在此条件下,不同碳原子数(C1~C5)的直链和支链醇均有较高的转化率,在短链醇的选择上具有宽广的适应性。超声波还减少了反应产物和反应体系中其他黏性杂质在固定化脂肪酶表面的吸附,回收的Novozym435相较单纯机械搅拌条件下回收的外观干净、分散良好无结块现象、易于洗涤和再次利用,具有良好的操作稳定性。  相似文献   

10.
非水介质中酶催化葡甘聚糖的转酯化反应   总被引:2,自引:0,他引:2  
葡甘聚糖(KGM)是一种具有优异的生物降解性、生物相容性、独特的生理和药理功能的天然聚多糖。通过环境友好的、高选择性的酶催化转酯化反应引入疏水基团可以制备葡甘聚糖的酯化衍生物,从而拓宽其应用领域。本研究探讨了在非水介质中以脂肪酶Novozym 435、Lipozym RMIM、Lipozym TLIM和Lipase TypeⅦ催化KGM和乙酸乙烯酯的转酯化反应,并且考察了相关因素对转酯化反应的影响。实验结果表明:在非水介质N,N-二甲基乙酰胺、甲苯和异辛烷中,脂肪酶Novozym 435可以较好的催化乙酸乙烯酯和KGM发生转酯化反应。以Novozym 435为催化剂、以异辛烷为反应介质,当底物浓度[S]=30(mg/mL)、酶用量[E]/[S]=0.30(wt/wt)、酰基供体乙酸乙烯酯用量[Acyl]/[OH]=3.0(mol/mol)、50℃、反应72 h的条件下,酯化KGM的取代度(DS)可达到0.49。  相似文献   

11.
tert-Butanol, as a novel reaction medium, has been adopted for lipase-catalyzed transesterification of rapeseed oil for biodiesel production, with which both the negative effects caused by excessive methanol and by-product glycerol could be eliminated. Combined use of Lipozyme TL IM and Novozym 435 was proposed further to catalyze the methanolysis and the highest biodiesel yield of 95% could be achieved under the optimum conditions (tert-butanol/oil volume ratio 1:1; methanol/oil molar ratio 4:1; 3% Lipozyme TL IM and 1% Novozym 435 based on the oil weight; temperature 35 °C; 130 rpm, 12 h). There was no obvious loss in lipase activity even after being repeatedly used for 200 cycles with tert-butanol as the reaction medium. Furthermore, waste oil was also explored for biodiesel production and it has been found that lipase also showed good stability in this novel system.  相似文献   

12.
The conversion of soybean oil to biodiesel fuel was investigated in the presence of a lipase from Thermomyces lanuginosus (commercially called Lipozyme TL IM) in a solvent-free medium. The lipase was inactivated when more than 1.5 molar equivalent of methanol was added to the oil mixture. To fully convert the oil to its corresponding methyl esters, the reaction was performed successfully by a three-step addition of 1 molar equivalent of methanol and under the optimized conditions (40°C, 150 rpm, 10% enzyme quantity based on oil weight), the maximum methyl ester (ME) yield was 98% after 12 h reaction. By-product glycerol had a negative effect on enzymatic activity and iso-propanol was found to be effective for glycerol removal, in the presence of which lipase expressed relatively high activity and more than 94% of the ME yield was maintained after being used repeatedly for 15 batches.  相似文献   

13.
The conversion of soybean oil to biodiesel fuel was investigated in the presence of a lipase from Thermomyces lanuginosus (commercially called Lipozyme TL IM) in a solvent-free medium. The lipase was inactivated when more than 1.5 molar equivalent of methanol was added to the oil mixture. To fully convert the oil to its corresponding methyl esters, the reaction was performed successfully by a three-step addition of 1 molar equivalent of methanol and under the optimized conditions (40°C, 150 rpm, 10% enzyme quantity based on oil weight), the maximum methyl ester (ME) yield was 98% after 12 h reaction. By-product glycerol had a negative effect on enzymatic activity and iso-propanol was found to be effective for glycerol removal, in the presence of which lipase expressed relatively high activity and more than 94% of the ME yield was maintained after being used repeatedly for 15 batches.  相似文献   

14.
The enzymatic synthesis of biodiesel by a high-pressure semi-continuous process in near-critical carbon dioxide (NcCO(2)) was studied. Biodiesel synthesis was evaluated in both batch and semi-continuous systems to develop an effective process. Batch processing demonstrated the advantageous properties of NcCO(2) as an alternative reaction medium. Three immobilized lipases (Novozym 435, Lipozyme RM IM, and Lipozyme TL IM from Novozymes) were tested, with Lipozyme TL IM the most effective, showing the highest conversion. Biodiesel conversion from several edible and non-edible oil feedstocks reached >92%. Higher conversion (99.0%) was obtained in a shorter time by employing repeated batch processes with optimized conditions: 44.3 g (500 mM) canola oil, a substrate molar ratio (methanol:oil) of 3:1, an enzyme loading of 20 wt% (of the oil used), at 30 °C, 100 bar, and 300 rpm agitation. The enzyme maintained 80.2% of its initial stability after being reused eight times. These results suggest that this method produces biodiesel energy-efficiently and environment-friendly.  相似文献   

15.
Enzymatic syntheses of biodiesel via alcoholysis of different vegetable oils (sunflower, borage, olive and soybean) have been studied. Loss of lipase activity induced by the nucleophile is greater with methanol than with ethanol, and is greater for Lipozyme TL IM than for Novozym 435. The optimum volume of ethanol depends on the loading of solid biocatalyst and is higher for preparations of Novozym 435 than for Lipozyme TL IM. Maximum rates were obtained with Lipozyme TL IM, for a molar ratio of alcohol to FA residues of 0.33. By contrast, Novozym 435 requires at least a 2:1 ratio. Alcoholysis of the vegetable oils is faster with Lipozyme TL IM than with Novozym 435. Use of a high loading of Novozym 435 (50% w/w) and a large molar excess of ethanol are required to obtain an initial rate similar to that obtained with Lipozyme TL IM at a lower enzyme loading (10% w/w) and an equimolar ratio of ethanol and FA residues. Novozym 435 produces quantitative conversions in only 7h at 25 degrees C, but complete conversions are not obtained with Lipozyme TL IM. Three stage stepwise addition of ethanol yields 84% conversion to ethyl esters for Lipozyme TL IM. Hence use of Novozym 435 is preferred. After nine cycles in a batch reactor Novozym 435 retained 85% of its initial activity.  相似文献   

16.
A study was made of the material balance for the fatty acid methyl ester (biodiesel) synthesis from sunflower oil using potassium hydroxide as the catalyst. A factorial design of experiments and a central composite design have been used to evaluate the influence of operating conditions on the process material balance. The responses chosen were the biodiesel yield and the yield losses due to triglyceride saponification and methyl ester dissolution in glycerol, while the variables studied were temperature, initial catalyst concentration and the methanol:vegetable oil molar ratio. The biodiesel yield increased and therefore the yield losses decreased by decreasing catalyst concentration and temperature. However, the methanol:sunflower oil molar ratio did not affect the material balance variables significantly. Second-order models were obtained to predict the biodiesel yield and both yield losses. Within the experimental range studied, these models largely matched the results from the experiments.  相似文献   

17.
This study consists of the development and optimisation of the potassium hydroxide-catalysed synthesis of fatty acid methyl esters (biodiesel) from sunflower oil. A factorial design of experiments and a central composite design have been used. The variables chosen were temperature, initial catalyst concentration by weight of sunflower oil and the methanol:vegetable oil molar ratio, while the responses were biodiesel purity and yield. The initial catalyst concentration is the most important factor, having a positive influence on biodiesel purity, but a negative one on biodiesel yield. Temperature has a significant positive effect on biodiesel purity and a significant negative influence on biodiesel yield. The methanol:vegetable oil molar ratio is only significant for the biodiesel purity, having a positive influence. Second-order models were obtained to predict biodiesel purity and yield as a function of these variables. The best conditions are 25 degrees C, a 1.3%wt for the catalyst concentration and a 6:1 methanol:sunflower oil molar ratio.  相似文献   

18.
The effect of different solvents and three different acyl acceptors on the transesterification of triolein (as a model compound) was investigated. The yield of biodiesel (methyl or ethyl ester) was monitored as a function of time. The yield of the product was also determined in a solvent-free system for two different modes of stirring. The results indicate that the highest yield is obtained in a solvent-free system with mechanical stirring. Methyl acetate is also effective as a solvent and acyl acceptor. Biodiesel was also produced by transesterification of triglycerides (triolein) present in olive oil with methanol and Novozym® 435. The effect of the molar ratio of methanol to triolein, mode of methanol addition, enzyme activity and reaction temperature on overall conversion and yield was determined. The final conversion and yield of biodiesel after a reaction time of 24 h were unaffected by changes in these parameters over the range studied. Preliminary findings indicate that the results obtained from small scale reactors and fresh oil can be extended to larger reactors and used oil.  相似文献   

19.
The effect of different solvents and three different acyl acceptors on the transesterification of triolein (as a model compound) was investigated. The yield of biodiesel (methyl or ethyl ester) was monitored as a function of time. The yield of the product was also determined in a solvent-free system for two different modes of stirring. The results indicate that the highest yield is obtained in a solvent-free system with mechanical stirring. Methyl acetate is also effective as a solvent and acyl acceptor. Biodiesel was also produced by transesterification of triglycerides (triolein) present in olive oil with methanol and Novozym® 435. The effect of the molar ratio of methanol to triolein, mode of methanol addition, enzyme activity and reaction temperature on overall conversion and yield was determined. The final conversion and yield of biodiesel after a reaction time of 24 h were unaffected by changes in these parameters over the range studied. Preliminary findings indicate that the results obtained from small scale reactors and fresh oil can be extended to larger reactors and used oil.  相似文献   

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