多相酶膜反应器合成生物活性二肽

生物活性肽;多相酶膜反应器合成生物活性二肽     

酶膜反应器及其在生物催化领域的应用

酶膜反应器是一种新型的生物催化反应设备,它是反应与分离相耦合的装置,集产品分离、纯化和酶回收利用于一体,具有其它方法不可比拟的优势。在强调资源节约,环境友好和清洁化生产技术的今天,显示一些特别的优点,近年来已成为热门的研究领域。本文主要介绍了酶膜反应器的基本原理、特征及其分类,并根据分类对近年来酶膜反应器在生物催化领域...     

复合纤维素膜固定化胰蛋白酶反应器及其应用于蛋白质酶解

合成了甲基丙烯酸缩水甘油酯-纤维素复合膜,并以此膜为基质共价键合固定化胰蛋白酶,以N-苯甲酰-L-精氨酰乙酯(BAEE)为底物,应用高效液相色谱系统测定了酶固定化膜柱的催化反应特性。研究结果表明:温度、pH值、离子强度、有机溶剂及蛋白变性剂等都对固定化酶的活力有一定的影响。在最适条件下,固定化胰蛋白酶的活力为17800U/g干膜,蛋白载量为3.6mg/g(≈0.15μmol/g)干膜,活性回收率达到52%.固定化酶表现出较高的使用和储藏稳定性,在40℃下,水解BAEE底物24h活力无显着变化。固定化酶膜柱在4℃冷藏保存100d仍保存90%以上的水解活力。固定化酶反应器被应用于蛋白质酶解的肽谱实验。     

Simultaneous Enzymatic Synthesis of Gluconic Acid and Sorbitol

With regard to the enzymatic synthesis of sorbitol and gluconic acid, a screening was carried out to identify promising producers of glucosefructose oxidoreductase (GFOR) and gluconolactonase (GL).Zymomonas mobilis DSM 473 andRhodotorula rubra DSM 70403 have been selected for the synthesis of GFOR and GL, respectively. Maximal enzyme production by these organisms has been achieved at D-glucose concentrations of 200 and 150 gJL, respectively. Both GFOR and GL were purified and characterized with respect to some of their catalytic properties. GL showed strict specificity for 1,5-(δ)-lactones and was activated by Mg²⁺ and Mn²⁺ ions. The potential use of soluble GFOR is limited by its inactivation during substrate conversion, and the effects of reaction temperature and pH on the “catalytic” stability of GFOR were evaluated. Exogenous adddition of auxiliary GL had no effect on oxidoreductase stability and did not improve productivities.

     

One-Step Enzymatic Synthesis of 1-Tuliposide A Using Tuliposide-Converting Enzyme

Applied Biochemistry and Biotechnology - 6-Tuliposides A (6-PosA) and B (6-PosB) are major secondary metabolites in tulip (Tulipa gesneriana), having an acyl group at the C-6 position of d-glucose....     

Modeling of Fischer-Tropsch Synthesis in a Slurry Reactor with Water Permeable Membrane

Fischer-Tropsch synthesis is an important chemical process for the production of liquid fuels and olefins. In recent years, the abundant availability of natural gas and the increasing demand of olefins, diesel, and waxes have led to a high interest to further develop this process. A mathematical model of a slurry membrane reactor used for syngas polymerization was developed to simulate and compare the maximum yields and operating conditions in the reactor with that in a conventional slurry reactor. The carbon polymerization was studied from a modeling point of view in a slurry reactor with a water permeable membrane and a conventional slurry reactor. Simulation results show that different parameters affect syngas conversion and carbon product distribution, such as the hydrogen to carbon monoxide ratio, and the membrane parameters such as membrane permeance.     

渗透汽化型酯化膜反应器研究 聚合物/无机固体酸管式复合膜的膜反应性能

设计了渗透汽化型管式膜反应器,以乙酸丁酯合成反应为探针,考察了Ｚｒ（ＩＶ）／ＰＶＡ,Ｚｒ（ＩＶ）－ＰＶＡ／ＰＶＡ两类聚合物担载无机固体酸管式复合膜的膜催化反应性能。探讨了功能膜的组成,结构,反应条件等对膜反应和分离性能的影响以及同步膜分离过程对反应转化的促进作用。实验结果表明,膜催化酯化反应过程主要是依赖与料液接触侧膜表面层的催化活性,膜的催化活性是影响反应速率,特别是初期反应转化速率的主要因素,后期的超平衡转化则依赖于膜分离过程     

固定化谷氨酸脱羧酶柱式反应器测定L-谷氨酸

用羧甲基化的N,N’-甲叉双丙烯酰胺交联的烯丙基葡聚糖(简称CM-CADB)凝胶树脂为新型载体,研究了谷氨酸脱羧酶(GDC)在CM-CADB上的固定化与环境的依赖关系.确定了酶固定化最佳条件,研究了固定化GDC的活性与底物浓度、pH、温度的依存性,动态响应特性,热稳定性和寿命,求算了米氏常数.将固定化GDC酶柱与进样系统具CO_2气敏电极的离子活度分析器-计算机数据采集系统匹配,构成酶反应谷氨酸检测装置,测定了固定化GDC酶柱的能斯特线性响应曲线,线性回归方程为y=43.3x+181.6,r为0.9936.     

A Two-Step Synthesis of Camphosultam

Modifications of the known route to camphosultam led to an easy two-step process. The unique intermediate is simply isolated by filtration. The overall yield is 66% on a hundred gram scale.     

A Two-Step Synthesis of Mimosamycin

The marine antibiotic mimosamycin, and a number of analogues, have been prepared in two steps by cycloaddition of a 1,4-benzoquinone or naphthoquinone with 2-aza-bis(1,3-t-butyldimethylsilyloxy)-1,3-buta-diene, hydrolytic work-up of the adduct, and phase-transfer catalysed alkylation of the resultant isoquinolin-3-ones.     

Efficient Synthesis of Dimethyl Ether from Methanol in a Bifunctional Zeolite Membrane Reactor

A sandwich FAU–LTA zeolite dual‐layer membrane has been developed and used as a catalytic membrane reactor for the synthesis of dimethyl ether (DME). In the top H‐FAU layer with mild acidity, methanol is dehydrated to DME. The other reaction product, water, is removed in situ through a hydrophilic Na‐LTA layer, which is located between the porous alumina support and the H‐FAU top layer. The combination of mild acidity with the continuous removal of water results in high methanol conversion (90.9 % at 310 °C) and essentially 100 % DME selectivity. Furthermore, owing to the selective and continuous removal of water through the Na‐LTA membrane, catalyst deactivation can be effectively suppressed.     

In-Situ Synthesis of Terbium Complex with Salicylic Acid in Silica Matrix by a Two-Step Sol-Gel Process

Sincesomelanthanideionspossessgoodlundnescentcharacteristicsbasedontheelectronictransitionsbetweenthe4fenergylevels,aseriesofrareearthcompoundshavebeenstudiedforpracticalapplicationsasphosphors.However,sincethef-ftransitionsoftheseionsareparityforbidden,theintensityofabsorptionbandsareusuallyrelativelyweak.Itiswellknownthatorganicligandsusuallyhavehighultravioletmolarabsorptivity.Ifthecomplexesthatcontainthiskindofligandsaresynthesized,theywillgivestrongluminescence.Infact,sofarmanyphotoactive…     

膜反应器中Ni-Cu催化剂上CO加氢合成乙烯的研究

 将硅藻土－TiO2－聚乙烯（或聚丙烯）疏水复合膜反应器应用于\r\nCO加氢合成乙烯的反应过程，以Ni－Cu／TiSiO和Ni－Cu／MgSiO为催化\r\n剂，考察了反应温度、空速和进料组成等因素对CO转化率和乙烯选择性\r\n的影响．结果表明：膜催化反应的产物与常规催化反应相同，催化反应\r\n机理没有区别，在适宜条件下，膜催化反应的CO转化率和乙烯选择性较\r\n之常规催化反应提高了10％左右，二氧化碳和甲烷的选择性降低，而乙\r\n烷的选择性略有增加．     

Monopalmityloxy Shikimic Acid: Enzymatic Synthesis and Anticoagulation Activity Evaluation

The monopalmityloxy shikimic acids have been synthesized from shikimic acid and palmitic acid catalyzed by Novozym 435 in 2-methyl-2-butanol. The anticoagulation activity in vivo via oral administration of monopalmityloxy shikimic acid has been evaluated through arteriovenous shunt model of rats and through the determination of thrombin time, prothrombin time, and activated partial thromboplastin time via rats. After reaction, the solid shikimic acid has been observed to dissolve in the reaction system completely. The subsequent high-performance liquid chromatography–mass spectroscopy analysis showed that the monopalmityloxy shikimic acids, as the only products, had been formed and the overall conversion rate was over 70%. The result showed that it had anti-thrombosis activity, could prolong the coagulating time and bleeding time in vivo, and lengthen the coagulating time in vitro. Compared with control group, the differences of the treatment group and aspirin group of rats are significant (P < 0.05) for prothrombin time and thrombin time, and very significant (P < 0.01) for activated partial thromboplastin time. It suggested that the product had the anticoagulation activity. The mechanism might be the co-action of the inhibition of intrinsic coagulation and the inhibition of extrinsic coagulation, and the inhibiting effect on intrinsic pathway is stronger than that on extrinsic pathway.     

模拟酶微型反应器中糠醛催化氧化为糠酸

在水与有机试剂组成的非均相体系中，用β－环糊精（β-cyclodextrin,缩写：β－CD）衍生物模拟生物酶，以强力搅拌下分散在有机溶剂中的小水珠作为微型反应器进行糠醛催化氧化为糠酸的反应，停止搅拌后体系立即分层，产物在有机相，残留的原料和模拟酶在水相。本合成方法简单，溶剂和模拟酶能回收，不产生污染，催化效率较均相高，为绿色合成化学制备医药、化工产品提供了一种新合成体系。     

Synthesis and Enzymatic Degradation of Aliphatic Polyesters Copolymerized with Trimesic Acid

Abstract

Network copolyesters were made from adipic acid and ethylene glycol with 10–40 mol% trimesic acid (Y). Prepolymers prepared by melt polycondensation were cast from dimethylformamide solution and postpolymerized at 260°C for various times to form a network. The degree of reaction (D _R), estimated from the infrared absorbance of hydroxyl and methylene groups, increased with increasing postpolymerization time and leveled out at about 90% after 4–6 hours. Heat distortion temperatures (T _h) measured by thermomechanical analysis increased greatly from ?83 to 48°C upon the incorporation of Y. Wide-angle x-ray diffraction patterns showed that the copolymer films are amorphous. Density, tensile strength, and Young's modulus decreased for the copolymers with 10–30 mol% Y, whereas they increased drastically for the copolymer with 40 mol% Y. The enzymatic degradation was estimated by the weight loss of the copolymer films in buffer solutions with a lipase at 37°C. The weight loss decreased remarkably with increasing Y and showed no weight loss for the copolymer with 40 mol% Y. On the other hand, the weight loss by alkali hydrolysis increased for the copolymers with 10 and 20 mol% Y, implying a difference in the degradation mechanism between enzymatic degradation and alkali hydrolysis.     

Enzymatic Synthesis of [3-14C]Cinnamic Acid

Convenient and efficient route of the synthesis of [3-¹⁴C] cinnamic acid is reported. [1-¹⁴C]Benzoic acid, prepared by carbonation of Grignard reagent with [¹⁴C]carbon dioxide, was reduced to [1-¹⁴C]benzyl alcohol. In the enzymatic step this alcohol was selectively oxidised to [1-¹⁴C]benzaldehyde using enzyme YADH (Ec. 1.1.1.1) and immediately condensed with malonic acid. This combined chemical and enzymatic approach allows to obtain [3-¹⁴C]cinnamic acid with radiochemical yield higher than 50% in respect to the starting alcohol.     

Green Enzymatic Synthesis of L-Ascorbyl Fatty Acid Ester: An Antioxidant

In green chemistry, biocatalysis using microwaves is a very attractive tool for various regioselective syntheses. L-Ascorbyl fatty acid esters were synthesized by an immobilized lipase from Bulkholderia multivorans using microwaves, with a dynamically enhanced rate of reaction and appreciable yield of around 80%. Microwave radiation had no effect on enzymic inactivation, however, synergism between microwaves and biocatalyst was observed.