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。     

黑曲霉表面展示南极假丝酵母脂肪酶B催化仲醇动力学拆分

光学活性仲醇是合成多种生物活性化合物的原料和关键中间体,微生物细胞表面展示酶在生物催化和生物转化制备生化产品等方面表现出良好的应用性。研究了黑曲霉表面展示南极假丝酵母脂肪酶B(Candida antarctica lipase B,CALB)制备的全细胞催化剂(AN-CALB)动力学拆分仲醇的催化性能。以2-辛醇作为反应底物,研究了酰基供体、2-辛醇与乙酸异丙烯酯物质的量比、AN-CALB添加量、水活度、温度及溶剂对AN-CALB催化2-辛醇拆分的影响,确定最优反应条件为:以乙酸异丙烯酯为酰基供体、2-辛醇与乙酸异丙烯酯物质的量比1∶1、AN-CALB添加量50 g·L-1、水活度0.11、温度45℃、以甲苯为溶剂,在此条件下,反应12 h的底物转化率达47.4%,eep值为99.6%,E值大于600。在最优反应条件下,AN-CALB对8种仲醇均表现出较好的拆分效果,底物转化率最高接近50%。该研究为仲醇动力学拆分提供了新的催化剂选择。     

游离脂肪酶NS81006催化含酸油脂制备生物柴油的应用研究

与固定化脂肪酶相比,游离脂肪酶具有反应速率快、成本较低的优势,成为制备生物柴油新的研究方向。前期研究结果表明,游离脂肪酶NS81006可以高效催化大豆油甲醇解制备生物柴油,进一步研究其对含酸油脂的催化,对于促进游离脂肪酶在生物柴油领域中的应用具有重要意义。本文系统研究了甲醇添加策略对游离脂肪酶NS81006催化油酸制备生物柴油的影响,进而考察了NS81006催化模拟酸化油以及实际含酸油脂制备生物柴油的转化情况。研究表明,在优化的甲醇添加策略下,游离脂肪酶NS81006可有效催化油酸、不同含酸量(0~100%,基于总质量)模拟酸化油以及实际含酸油脂进行生物柴油的制备;离心分离可有效实现NS81006的回复使用,连续回用5个批次,游离脂肪酶活性未出现明显下降。     

生物酶法制备生物柴油研究现状及展望

就生物酶法制备生物柴油的研究现状进行了扼要的综述,探讨了固定化脂肪酶法、液体酶法和全细胞催化法制备生物柴油应用基础研究的进展及发展前景,指出影响生物酶法生产生物柴油产业化的因素及解决措施.     

生物酶法转化酵母油脂合成生物柴油

以一株高产油脂圆红冬孢酵母菌(Rhodosporidum toruloides Y4#)干菌粉为原料,利用酸热法提取了该酵母油脂,并对所得油脂进行了分析. 进一步利用该酵母油脂为原料分别研究了无溶剂体系中三步甲醇法及在叔丁醇介质体系中脂肪酶催化合成生物柴油,发现脂肪酶可以有效转化该酵母油脂制备生物柴油. 在优化反应条件下,生物柴油得率可达90%左右,略低于相同条件下利用精制大豆油合成生物柴油的得率.     

毕赤酵母表面展示脂肪酶催化合成肉豆蔻酸糖酯

研究了毕赤酵母表面展示脂肪酶(CALB)全细胞催化剂的较佳活性条件,结果显示,适宜的反应温度为50~60℃。以CALB为催化剂,比较了不同底物对糖酯合成的影响。以1,2-O-异亚丙基-D-呋喃葡萄糖(Ip Glc)为酰基受体,肉豆蔻酸为酰基供体,考察了有机溶剂种类、CALB的添加量、底物摩尔比、分子筛的添加量、初始水活度对合成6-O-肉豆蔻基-1,2-O-异亚丙基-α-D-呋喃型葡萄糖酯(Ip Glc-C14)的影响,得到较佳的合成条件为:丙酮5 m L、CALB(干粉)0.3 g、n(Ip Glc)∶n(肉豆蔻酸)=1∶3(其中Ip Glc 0.5 mmol)、4A分子筛0 g、初始水活度a_w=0.11、反应温度50℃、200 r/min反应72 h。在此条件下,Ip Glc-C14的收率为91.25%。比较了CALB和固定化脂肪酶Novozym 435对Ip Glc-C14合成的反应进程的影响,结果显示使用Novozym 435的反应速率快,而CALB的最终收率较高。     

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.     

固定化酶及全细胞生物催化合成生物柴油的研究进展

生物柴油是一种可再生的绿色环保型能源.酶法合成生物柴油具有条件温和、醇用量小、甘油易回收等优点.本文综述了固定化脂肪酶、全细胞生物催化剂在生物柴油制备中研究应用的新进展.     

固定化脂肪酶催化酯交换制备生物柴油的研究进展

生物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。介绍了固定化脂肪酶在催化油脂酯交换制备生物柴油方面的应用,对影响酯交换反应的脂肪酶源、底物摩尔比率、酰基受体、水含量、反应温度、副产物等因素进行了综述。     

固定化脂肪酶催化废油合成生物柴油

研究了固定化假丝酵母99-125脂肪酶在有溶剂的体系下催化废油合成生物柴油过程中,油醇摩尔比、有机溶剂性质、底物浓度、体系含水量、甲醇流加等因素对反应过程的影响.研究结果表明,在最佳实验条件下,反应转化率最高可达92％,酶的使用寿命可达7批以上.     

Esterification patterns of lipases for synthesizing tricaproylglycerols in organic solvent

To investigate the synthetic patterns of triglyceride (triacylglycerol) by lipases in organic solvent, esterification patterns of triglyceride, diglyceride, and monoglyceride were monitored at various reaction times with 10 lipases. As a model study, tricaprin was synthesized from glycerol and capric acids (C_10:0) in isooctane. Lipases that were known to give nonspecific hydrolysis in aqueous solvent, such as lipase from Candida cylindracea, Lipase OF-360 (from C. rugosa), and Lipase MY (C. rugosa) showed nonspecific synthesis of tricaprin in organic solvent (Group I). There are two groups for esterifying trigly cerides in organic solvent with 1,3-specific lipases: one consists of the lipases from Rhizomucor miehei, Pseudomonas aeruginosa (Lipase PS), and Chromobacterium viscosum (Lipase CV) (Group II), and another (Group III) is represented by Lipase AP (Aspergillus niger), Lipase FAP-15 (Rhizopus javanicus), and Lipase D (R. delemar). Although both groups showed 1,3-specific hydrolysis in aqueous solvent, Group III has stricter 1,3-specificity for the synthesis of tricaprin from dicaprin.     

Factors influencing the activity and thermostability of immobilized porcine pancreatic lipase

Lipase from porcine pancreas was immobilized on cellulose beads having various degrees of hydrophobicity, by covalent linking and by hydrophobic adsorption. Lipolytic activity was measured in heterogeneous organicaqueous systems of various hydrophobicities using olive oil as a substrate. The main factors influencing lipase activity were hydrophobicity of the reaction mixture and of the carrier. Carriers with increased hydrophobicity enhanced lipase activity more than less hydrophobic ones. Lipase immobilized covalently on cellulose beads was less active than that adsorbed onto tritylcellulose but was considerably more thermostable.     

大孔载体固定化脂肪酶

用自制大孔载体固定化脂肪酶,对固定化条件进行了优化,比较了固定化酶与游离酶的酶学参数. 结果表明,酶粉与载体质量比为1:1、固定化温度在20~25℃之间、固定化时间1.5 h的条件下,所得固定化酶的酶活最高. 固定化酶的最适pH为8.5,最适温度为40℃,其热稳定性、操作稳定性都比游离酶高,4℃下保存7 d后,酶活仍剩余94%.     

用于环保的耐热脂肪酶产生菌Wi-3的诱变及其酶学特性研究

从福州温泉澡堂排水道中分离筛选到一株可用于环保的耐热脂肪酶产生菌株Wi-3,经UV NTG复合诱变,选育出突变株Wi-3-3和Wi-3-5,其酶活比出发菌株分别提高了32.3%和11.8%.对Wi-3-3的产酶条件进行研究,结果表明在35℃、起始pH值7.0、250 mL摇瓶装量为35 mL、接种量为4 mL(菌浓1.5×108个·mL-1)、发酵周期为35 h的培养条件下产酶最高.用硫酸铵提取Wi-3-3发酵液中脂肪酶进行酶学特性的初步研究,结果表明其最适反应pH值为8.6、最适反应温度为55℃.     

Lipase-catalyzed resolution of 1-hydroxymethyl-2-methylferrocene

±-1-Hydroxymethyl-2-methylferrocene was optically resolved by transesterification with lipases using vinyl esters such as vinyl butyrate, vinyl caproate, vinyl octanoate and vinyl decanoate, as acyl donors.     

Lipase purification by various techniques and its thermostabilization in presence of surface active additives

Crude porcine pancreatic lipase was purified by removing water-insoluble impurities (residual lipid material) associated with it by a conventional method, using hydrotropic additives and by liquid coacervate extraction. Maximum yield with good recovery of activity was obtained when hydrotropes were used to separate the associated lipids from lipase. The thermostability of the enzyme was also checked in the solutions of additives such as sodium butyl monoglycol sulfate (Na-BMGS), proline and Triton X-114. In Na-BMGS solutions above a concentration of 0·2 mol dm⁻³ the lipase activity decreased beyond 50°C whereas in 1 mol dm⁻³ proline solution it was retained even at 80°C, showing a good thermostabilizing effect. However, in the presence of Triton X-114 the enzyme was completely inactivated with increase in temperature. © 1998 SCI.     

响应面法优化固定化洋葱伯克霍尔德菌脂肪酶回收工艺的研究

酶法制备生物柴油工艺引起了越来越多的关注。本文以脂肪酶回收前后脂肪酸甲酯得率之比作为检测指标,采用响应面法对自行制备的固定化洋葱伯克霍尔德菌脂肪酶的回收工艺参数进行了优化,并利用软件SAS 9.0对实验数据进行分析。确定的最佳回收条件:回收溶剂用量20.4 mL,回收温度40.2℃,回收时间20 m in。此条件下,验证试验脂肪酶回收率最大可达98.26%,与回归模型预测最优条件下脂肪酶回收率99.59%非常接近,且使用30次后,其回收效率依然接近100%。R2=96.63%显示该回归模型在分析脂肪酶回收率方面具有极高的准确性和可信度。     

Castor bean lipase as a biocatalyst in the esterification of fatty acids to glycerol

Castor bean lipase was investigated as biocatalyst in the esterification of fatty acids to glycerol. For this purpose, pressed seeds were pretreated with phosphate-citrate buffer solution at optimal preincubation time and pH and used as a lipase source in esterification of fatty acids with glycerol. The effect of process parameters in the esterification, i.e., molar ratios of reactants, temperature, water content of glycerol and concentration of lipase, were determined by using pretreated castor bean.