响应面法乌桕脂制备生物柴油研究

探讨了以乌桕脂为原料,叔丁醇体系利用脂肪酶催化制备生物柴油的工艺。通过响应面法优化,获得最佳工艺条件为:2.5 g乌桕脂中加入0.6 mL甲醇,0.75 mL叔丁醇和9%脂肪酶,50℃反应16 h,生物柴油得率为92.34%;脂肪酶回收利用10次,生物柴油得率仍能保持在85%以上。     

新型反应介质中脂肪酶催化多种油脂制备生物柴油

用叔丁醇作为反应介质,利用固定化脂肪酶催化油脂原料甲醇醇解反应制备生物柴油,消除了甲醇和甘油对酶的负面影响,酶的使用寿命显著延长. 用菜籽油作原料,叔丁醇和油脂的体积比为1:1,甲醇与油脂的摩尔比为4:1,3%的Lipozyme TLIM和1%的Novozym 435结合使用,35℃下130 r/min反应12 h,生物柴油得率可达95%. 该工艺在200 kg/d的规模下制得的生物柴油产品完全满足美国和德国生物柴油标准,脂肪酶重复使用200批次,酶活性基本没有下降. 且在叔丁醇介质体系中大豆油、桐籽油、棉籽油、乌桕油、泔水油、地沟油和酸化油都能被有效转化成生物柴油且脂肪酶保持很好的稳定性.     

生物柴油合成中脂肪酶的应用研究进展

生物柴油是以动植物油脂为原料制造的可再生能源,可作为石油柴油的替代或部分替代燃料.生物柴油的发展不仅有利于解决能源问题,而且可以减少温室气体的排放量.本文对脂肪酶的催化活性和选择性,脂肪酶的固定化、不同反应体系中生物柴油的脂肪酶催化合成及其操作条件,不同酰基受体对脂肪酶催化制备生物柴油的影响等问题的研究进展进行了综述.     

张国玲,杜伟,刘德华

油脂酵母具有高产油能力,并且所积累油脂的主要成分与植物油脂相似,可作为生物柴油制备的原料.本文对影响酵母油脂合成的关键酶、基因、碳源以及酵母油脂在生物柴油制备中的研究进展进行了综述,认为ATP∶柠檬酸裂解酶和苹果酸酶是酵母油脂合成代谢途径中的关键酶,另外,LRO1、DGA1和ARE基因也被认为同油脂合成有着紧密联系.对酵母油脂用于生物柴油生产的前景进行了展望:利用廉价碳源如甘油、能源作物以及木质纤维素水解液等培养酵母,可有效降低生产成本.在不同催化方法下,酵母油脂均可用于制备生物柴油,这对进一步研究生物柴油的生产应用有着重要意义.     

酵母油脂及用于生物柴油制备研究进展

油脂酵母具有高产油能力,并且所积累油脂的主要成分与植物油脂相似,可作为生物柴油制备的原料。本文对影响酵母油脂合成的关键酶、基因、碳源以及酵母油脂在生物柴油制备中的研究进展进行了综述,认为ATP∶柠檬酸裂解酶和苹果酸酶是酵母油脂合成代谢途径中的关键酶,另外,LRO1、DGA1和ARE基因也被认为同油脂合成有着紧密联系。对酵母油脂用于生物柴油生产的前景进行了展望：利用廉价碳源如甘油、能源作物以及木质纤维素水解液等培养酵母,可有效降低生产成本。在不同催化方法下,酵母油脂均可用于制备生物柴油,这对进一步研究生物柴油的生产应用有着重要意义。     

复合固定化脂肪酶催化餐厨废弃油脂合成生物柴油

探讨了复合固定化脂肪酶(Rhizopus oryzae lipase和Candida rugosa lipase)催化餐厨废弃油脂合成生物柴油的工艺条件。实验结果表明,单独使用1,3位专一性脂肪酶R.oryzae lipase催化餐厨废弃油脂,反应18h,生物柴油转化率达到70%;单独使用非专一性脂肪酶C.rugosa lipase,反应30h,生物柴油转化率可达20%。为了更有效提高生物柴油转化率,采用1,3位专一性脂肪酶R.oryzae lipase和非专一性脂肪酶C.rugosa lipase复合固定化脂肪酶催化合成生物柴油,反应21h,生物柴油转化率可达到96.5%。同时对该复合酶的稳定性进行了实验,在连续催化反应10个批次(300h)后,生物柴油转化率仍保持在80%以上。     

非水相脂肪酶催化大豆油脂合成生物柴油的研究

脂肪酶Lipozyme TL IM在非水相体系中能有效催化大豆油脂转化生成生物柴油.在优化条件下(醇油摩尔比41,反应温度40C,硅胶负载脂肪酶与油的质量比为60%),反应5h后产物脂肪酸甲酯得率可达92%.实验证明加入有机溶剂以及分批加入甲醇等均能有效提高本反应体系中脂肪酶的催化活性.     

具协同催化效应的毕赤酵母全细胞催化生物柴油制备

以表面共展示具协同催化效应的南极假丝酵母脂肪酶B(Candida antarctica lipase B,CALB)与嗜热丝孢菌脂肪酶(Thermomyces lanuginosus lipase,TLL)重组毕赤酵母全细胞作为催化剂催化生物柴油制备,考察了生物柴油制备条件,并进行了初步优化。结果表明,共展示CALB与TLL脂肪酶毕赤酵母全细胞在叔丁醇介质体系中可有效催化生物柴油制备。冻干酵母细胞量0.31 g/g油,醇油摩尔比4∶1,温度35℃,反应36 h,生物柴油得率达86.25%。     

固定化Candida sp.99-125脂肪酶催化大豆油合成脂肪酸乙酯

探讨了酶法合成脂肪酸乙酯作为生物柴油的可行性. 以大豆油和乙醇为原料,利用本实验室自制的固定化Candida sp. 99-125脂肪酶催化反应,深入研究水含量、溶剂量、脂肪酶量及反应温度等因素对酶法合成脂肪酸乙酯的影响. 结果表明,以大豆油质量为基准,在水含量为 12.5%(w)、溶剂正己烷为3 mL/g、脂肪酶量为20%(w)、温度40℃的优化反应条件下,3次流加乙醇,170 r/min摇瓶反应,12 h后可以达到96.8%的最高酯得率. 进一步研究表明,在此优化反应条件下,连续使用14批脂肪酶酯得率可保持70%以上.     

固定化R.oryzae细胞发酵产胞内脂肪酶及其催化制备生物柴油

采用含胞内脂肪酶的微生物细胞催化油脂原料生产生物柴油是目前生物柴油生产领域的一个新的研究方向.探讨了以聚氨酯泡沫颗粒作为载体固定化R.oryzae细胞对细胞生长与产胞内脂肪酶的影响,并对固定化R.oryzae发酵条件进行了优化,特别对氮源的选用进行了研究.结果表明,选用廉价的豆粉作为有机氮源培养R. oryzae细胞效果较好,与以蛋白胨作为培养基氮源相比,单位培养基所得菌体的总酶活提高至1.55倍,同时,氮源利用率大大提高.进一步考察了有机氮源与无机氮源复合培养R.oryzae细胞的情况,发现豆粉与(NH4)2 HPO4复合效果较好.利用正交设计对培养基中各种无机盐成分进行了优化.优化结果为全脂豆粉2%,大豆油3%,MgSO4 0.035 %, K2HPO4 0.12 %,(NH4)2 HPO4 0.10 %,上述培养条件下,单位培养基培养菌体胞内脂肪酶活可达6054.2 U·L-1培养基.以该条件下培养菌体催化大豆油生产生物柴油,在叔丁醇体系下,反应24 h生物柴油得率可达68.5%.     

微波强化棉籽油制备生物柴油的研究

利用微波强化以棉籽油和甲醇为原料,KOH为催化剂制备生物柴油。考察醇油摩尔比、催化剂用量、反应时间和微波功率对酯交换反应的影响。结果表明,醇油摩尔比为9∶1,催化剂用量为1.0%,反应时间为3 min,微波功率360 W为最优反应条件。在此反应条件下生物柴油产率可达94%。与传统合成方法相比,该方法可缩短反应时间30~35 min。所得生物柴油主要质量指标达到我国和欧洲(EN14214)生物柴油质量标准,通过红外光谱分析表明,棉籽油生物柴油具有生物柴油所含的官能团。     

Potassium hydroxide catalyst supported on palm shell activated carbon for transesterification of palm oil

In this study, potassium hydroxide catalyst supported on palm shell activated carbon was developed for transesterification of palm oil. The Central Composite Design (CCD) of the Response Surface Methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst loading and methanol to oil molar ratio on the production of biodiesel using activated carbon supported catalyst. The highest yield was obtained at 64.1 °C reaction temperature, 30.3 wt.% catalyst loading and 24:1 methanol to oil molar ratio. The physical and chemical properties of the produced biodiesel met the standard specifications. This study proves that activated carbon supported potassium hydroxide is an effective catalyst for transesterification of palm oil.     

叔戊醇体系酶促大豆油制备生物柴油

叔戊醇作为反应介质,固定化脂肪酶Novozym 435催化大豆油与甲醇的转酯反应制备生物柴油。叔戊醇消除了反应底物甲醇及反应副产物甘油对酶活的负面影响。定量分析表明,叔戊醇与油脂的体积比为1,甲醇与油脂的摩尔比为3,2%脂肪酶,反应体系含水量2%,40 ℃、180 r/min条件下反应15 h,生物柴油得率可达97%。在最适条件下反应进行160批次,酶仍保持了较高的活性和良好的稳定性。     

亚临界甲醇中麻疯树油制备生物柴油的研究

对麻疯树油在催化剂对甲苯磺酸作用下与亚临界甲醇反应制备脂肪酸甲酯(生物柴油)进行了研究。结果表明在反应温度170℃、醇油摩尔比40:1、催化剂用量占油重的0.75%和反应时间30 m in的条件下,反应产物中脂肪酸甲酯含量可达93%以上。制备的生物柴油,各项指标与柴油相似。主要性能指标,符合ASTMPS121-99(USA)和0#矿物柴油标准。     

Biodiesel of tucum oil,synthesized by methanolic and ethanolic routes

Biodiesel was obtained by transesterification of tucum oil in anhydrous ethanol and methanol and employed NaOH as catalyst. The products obtained were characterized by physical chemical, NMR, FTIR, CG and thermogravimetric analysis. It could be concluded that the properties of the two types of biodiesel (ethanolic and methanolic) were very similar when compared with diesel oil.     

In situ transesterification of coconut oil using mixtures of methanol and tetrahydrofuran

The conventional biodiesel production method requires oil extraction followed by transesterification with methanol. The solubility of vegetable oils in methanol is low which decreases the overall rate of reaction. To eliminate the oil extraction step and improve the overall reaction rate, simultaneous extraction, esterification and transesterification were conducted by directly mixing methanol and tetrahydrofuran (THF) co-solvent and sulfuric acid catalyst with ground, desiccated coconut meat (copra) in a batch process and continuing the reaction until the system reached steady state. After separation of the mixture, yield was obtained by measuring the content of triglycerides, diglycerides and monoglycerides in the biodiesel phase. The yield increases with THF:methanol ratio, methanol:oil molar ratio and temperature. Within the range of conditions tested, the highest yield achieved was 96.7% at 60 °C, THF:methanol volume ratio of 0.4 and methanol:oil molar ratio of 60:1. The methanol:oil molar ratio is necessarily high in order to completely wet the copra mass, but is still lower than in previous studies by other researchers on in situ transesterification. Product assays show that the resulting biodiesel product is similar to conventionally produced coconut biodiesel. The results indicate that the in situ transesterification of copra using methanol/THF mixtures merits further study.     

Comparison of methods for preventing methanol inhibition in enzymatic production of biodiesel

During the enzymatic production of biodiesel, methanol has a major inhibitory effect on enzyme activity whereas glycerol has a minor effect. Revitalization of the methanol-deactivated enzyme or pre-incubation of enzyme with various chemicals turned out to be unsuccessful. The stepwise feeding of methanol, a widely used conventional method for preventing methanol inhibition, was optimized in terms of the aliquot number and feeding interval to obtain a high conversion rate as well as a high degree of final biodiesel conversion. The use of six feedings of methanol with an equivalent molar ratio of 0.75 at 3-h intervals was found to be the optimal mode for preventing methanol inhibition; a biodiesel conversion rate of approximately 95% could be achieved within 20 h by using this method. Finally, to prevent contact between the undissolved methanol and the enzyme, methanol was pre-dissolved in water or biodiesel and fed to the mixture of soybean oil and the enzyme. This pre-dissolution method completely prevented enzyme inhibition, and a final biodiesel conversion rate of 82.3% was obtained.     

New process for catalyst-free biodiesel production using subcritical acetic acid and supercritical methanol

The production of glycerol as a by-product is unavoidable in the current conventional biodiesel manufacturing processes. Since biodiesel production is expected to increase in the near future, effective utilization of glycerol will become an issue of interest. In this study, therefore, a process consisting of subcritical acetic acid treatment to convert rapeseed oil to fatty acids and triacetin followed by conversion of the obtained fatty acids to their fatty acid methyl esters in supercritical methanol treatment was investigated. The obtained results clearly revealed that this two-step reaction could proceed effectively at a high reaction rate, and that fatty acid methyl esters and triacetin could be obtained under milder reaction condition than the one-step process utilizing supercritical methyl acetate and supercritical methanol.     

固体碱催化黄连木籽油制备生物柴油

制备了K2CO3/Mg(A l)O固体碱催化剂,适宜制备条件为:K2CO3负载量30%、在700℃下焙烧4 h。用比表面积测定仪、X射线衍射仪、红外光谱仪对其进行了表征。以黄连木籽油为原料,开展了酯交换法制备生物柴油的研究,考察了主要影响因素:醇油摩尔比、催化剂用量、反应时间和反应温度对酯交换反应的影响,得到的酯交换反应适宜条件为:以黄连木籽油0.01 mol计,醇油摩尔比12∶1、催化剂用量为黄连木籽油质量的4.0%、反应时间2.5 h、反应温度68℃。在该条件下生物柴油的收率可达99%以上。催化剂经4次循环使用,生物柴油收率仍可保持在96%以上。用FTIR1、HNMR对所制备的产品进行了表征,证明产品中含有饱和脂肪酸甲酯和不饱和脂肪酸甲酯。