酶法合成头孢氨苄的反应—膜萃取耦合过程

发布时间：2018-05-10 07:04

本文选题：头孢氨苄 + 反萃相预分散　；参考：《天津大学》2014年硕士论文

【摘要】：头孢氨苄由于其抗菌谱广、生物利用度高、耐受性强等优点，是头孢菌素类抗生素中应用最广的品种之一。工业上常用化学合成方法制备，对环境造成了严重污染。酶法制备具有工艺操作简单、反应条件温和、周期短、无需基团保护、清洁安全等优点。基于此，本文研究了酶法合成头孢氨苄，并与反萃相预分散式支撑液膜（HFSLM-SD）分离方法耦合，以提高底物利用率和产物收率。文章首先介绍了HFSLM-SD萃取头孢氨苄过程的机理，并在此基础上建立了HFSLM-SD萃取头孢氨苄过程总传质系数模型。得到稳态下进料侧、膜内和反萃侧分传质系数分别为：ka=6.99×10-6m/s，km=1.5×10-6m/s，ks=6.681×10-5m/s，K=3.891×10-6m/s。其次，对HFSLM-SD萃取头孢氨苄过程进行了实验。分别考察了头孢氨苄原料液的性质及缓冲液的选择、反萃液的选择、有机膜相的组成以及进料浓度、相体积比、混合速率、跨膜压差对萃取效果的影响，得到了最优操作条件：进料相选择含20mM头孢氨苄的0.05M的碳酸盐缓冲液，pH在8.0～9.0之间；有机溶剂为Isopar L，与进料相的体积比为1:1，，载体Aliquat336浓度为5wt%；反萃相为pH=9.0的30mM PGME溶液；反萃相混合速率为400rpm；跨膜压差为4psi。同时开展了HFSLM-SD萃取头孢氨苄过程的动力学研究。最后，建立了酶法合成头孢氨苄的动力学模型，在实验的基础上计算了各反应速率常数，得到各步反应速率常数分别为k1=17.3(mMmin)-1，2=740(min)-1，k3=174(mMmin)-1，k-3=113(mMmin)-1。此外，对青霉素G酰基转移酶的活性进行了考察，讨论了络合剂的选择问题，最后进行了酶法合成头孢氨苄的反应-膜萃取耦合过程的实验，实现了头孢氨苄合成与分离的同步进行。最终得到的头孢氨苄用傅里叶变化红外光谱确认其结构。计算头孢氨苄的总收率为39.7%。酶法合成头孢氨苄的反应-膜萃取耦合过程同时解决了头孢氨苄收率低和难从反应体系中分离提纯的问题，用反萃相预分散式支撑液膜的方法，简化了操作步骤，提高了底物利用率与产物收率。
[Abstract]:Cefalexin is one of the most widely used cephalosporins because of its wide antibacterial spectrum, high bioavailability and strong tolerance. The common chemical synthesis method in industry has caused serious pollution to the environment. Enzymatic preparation has the advantages of simple operation, mild reaction conditions, short period, no group protection, clean and safe. Based on this, the enzymatic synthesis of cefalexin was studied and coupled with the separation method of stripping phase pre-dispersive supported liquid membrane HFSLM-SD, in order to improve the substrate utilization rate and the yield of the product. In this paper, the mechanism of Cefalexin extraction by HFSLM-SD is introduced, and the total mass transfer coefficient model of Cefalexin extraction by HFSLM-SD is established. The mass transfer coefficients of the feed side, the in-membrane and the counter-extraction side at the steady state are 6.99 脳 10 ~ (-6) m 路s ~ (-1) / s ~ (-1) 脳 10 ~ (-6) m 路s ~ (-1) = 6.681 脳 10 ~ (-5) m 路s ~ (-1) K ~ (-1) = 3.891 脳 10 ~ (-6) m 路s ~ (-1) respectively. Secondly, the extraction process of cefalexin by HFSLM-SD was studied. The effects of the properties of cefalexin solution and buffer solution, the selection of stripping solution, the composition of organic membrane phase, the concentration of feed material, the volume ratio of phase, the mixing rate and the pressure difference across membrane on the extraction effect were investigated. The optimum operating conditions were obtained as follows: the pH of 0.05M carbonate buffer containing 20mM cefalexin was between 8.0 and 9.0, the volume ratio of organic solvent to feed phase was 1: 1, and the concentration of Aliquat336 was 5 wt. the stripping phase was 30mM PGME solution of pH=9.0. The mixing rate of the stripping phase is 400rpm, and the transmembrane pressure difference is 4psi. The kinetics of HFSLM-SD extraction of cefalexin was also studied. Finally, a kinetic model for the enzymatic synthesis of cefalexin was established, and the rate constants of each reaction were calculated on the basis of experiments. The reaction rate constants of each step were determined to be K _ (1) ~ (17. 3) m ~ (1) M _ (min) ~ (-1) ~ (2) 740min ~ (-1) ~ (-1) K _ (3N) ~ (174) m _ (min) ~ (-1) ~ (-1) -3113mm ~ (-1) ~ (-1). In addition, the activity of penicillin G acyltransferase was investigated, and the selection of complexing agent was discussed. Finally, the reaction membrane extraction coupling process of enzymatic synthesis of Cefalexin was carried out. The synthesis and separation of cefalexin were carried out synchronously. The structure of Cefalexin was confirmed by Fourier transform infrared spectroscopy (FTIR). The total yield of cefalexin was 39.7. The coupling process of enzymatic synthesis of cefalexin with membrane extraction has solved the problems of low yield of cefalexin and difficulty in separation and purification from the reaction system. The utilization ratio of substrate and the yield of product were improved.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R914

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