超临界流体中物质溶解度的研究(Ⅰ)

本文分析了超临界流体萃取过程的特点.认为超临界流体的P-V-T行为可采用某种气体状态方程来描述.在分离作用机理上更近于液液萃取过程.提出了其萃取历程的物理化学模式,据此推导了超临界流体中物质溶解度计算公式.通过对此式的剖析和简化,得到了固体及液体纯物质在超临界流体中溶解度的半理论、半经验计算公式.并用文献发表的实验数据对半经验式的适用性进行验算,获得了较满意的结果,平均偏差≤10%.     

高效毛细管电泳技术及其应用

高效毛细管电泳(High Performance Capillary Electrophotesis,缩写为HPCE)又称毛细管区带电泳,是近年来发展起来的一种新型分离技术。由于这一技术具有高压液相色谱和凝胶电泳的优点,并且具有快速、分辨率高、重复性好的特点,已在国际学术界引起强烈的反响和关注。     

从微生物细胞中分离提取PHB的方法的综述

介绍和归纳目前文献报导的从微生物细胞中分离提取ＰＨＢ的各种方法，包括溶剂萃取法，化学试剂法，机械破碎法和酶法。对这些方法的优缺点进行了评述，提出发展机械的，物理的，化学的，生物的多种方法相结合以去除菌体中非ＰＨＢ的杂质来分离提取ＰＨＢ半是今后研究的一个方向。     

Rhodococcus rhodochrous tg1-A6腈水解酶的表达和催化研究

采用紫外线和氯化锂诱变得到一株名为Rhodococcus rhodochrous tg1-A6的菌种,该菌经过培养基和培养条件的优化能够产生高酶活的腈水解酶.优化培养条件为温度28℃、摇床转速200r/min、种子培养20h后以6%接种量接种于产酶培养基,初始pH 7.0,300mL摇瓶装液量为40mL.酶活达到21.96 U/mL.在含一定菌体的100 mL反应体系中,经过10 h连续43次补加底物丙烯腈,能使产物丙烯酸的质量浓度累积到414.5g/L.     

A STUDY ON TWO-PHASE FLOW CHARACTERISTICS IN PULSED SIEVE PLATE COLUMN FOR LIQUID-LIQUID EXTRACTION

In a previous investigation in 1963 Wang and Shen et al,found that the well known flow equationfor pulsed sieve plate column given by J.D.Thornton should be modified and written asV_s=V_d/X V_c/(1-x)=V_0(1-x)~nThis paper is a continuation of the previous works.Four kinds of liquid-liquid system were examinedin this study.The parameters n and V_o,the Sauter mean diameter of dispersed droplets D_(3.2) arc corro-leted in terms of physical properties of the systems and operation variables.Calculated flooding veloci-ties are close to the experimental values with deviation within ±15%.     

透明颤菌血红蛋白基因和λ噬菌体裂解基因在生产PHB重组大肠杆菌中的同时表达

Exogenous Vitreoscilla globin gene (vgb), lytic genes of phage γ with S amber mutation (S^-RRz) and poly(fl-hydroxybutyrate) (PHB) biosynthetic genes (phbCAB) were cloned into a same Escherichia coil cell,simultaneously or respectively. Six novel strains containing phbCAB and vgb with or without lytic genes were constructed. Strain VG1 (pTU14), in which vgb, phbCAB and S-RRz could all be successfully expressed, has superior characteristics in cell growth and PHB accumulation, while the results of strains containing vgb and phbCAB without S- RRz were not better than that of strains harbored phbCAB only. The simultaneous expression of vgb and S-RRz in the recombinant VG1 (pTU14) showed a great potential for low-cost production of PHB.     

有效增强重组腈代谢酶系表达活性的策略

讨论并提出了有效增强重组腈代谢酶系表达活性的多种策略。根据所选用的载体和宿主的不同表达特性,同时克隆目的基因上、下游的正向调控序列可直接增强酶表达水平;强化翻译后的修饰,可有效提高活性;除了常用的大肠杆菌克隆表达体系外,开发新型宿主-载体系统可为重组酶的活性表达提供新的途径;随着生物信息学技术的迅速发展,利用已知三维结构的蛋白对目标酶进行突变位点设计及结构与功能预测,将有望加快腈代谢酶系的定点突变研究进程。     

表面活性剂在生物工程中的应用之一—反胶团萃取

反胶团萃取分离蛋白质是一种新型的、有发展前途的生物产品的分离技术。它是利用表面活性剂在有机溶剂中形成反向胶团,从而实现了对蛋白质的萃取,是表面活性剂在生物工程中的一种成功应用。     

EXTRACTION OF INTERFERON-γ USING PEG/K_3PO_4 AQUEOUS TWO-PHASE SYSTEM

The aqueous two-phase system of PEG-4000/K_3PO_4 is selected to extract interferon-γ(γ-IFN)from the broth of homogenized E.coil cells,which were recombined genetically and werefermented in high expressivity.The effects of pH value and the concentrations of PEG and phos-phate on the partition behavious of γ-IFN and contaminating proteins have been investigated.Theresults show that the pH value is the most influential factor effecting the extraction yield of γ-IFN.Under a suitable condition,an effective separation with high yield of γ-IFN can be achieved.     

耦合末端盐桥与定点突变的重组腈水合酶催化动力学

双亚基腈水合酶是催化丙烯腈水合生产丙烯酰胺的重要工业酶。通过Discovery Studio 2.5软件对C-末端盐桥耦合定点突变改造的耐热型基因重组腈水合酶NHase^M-TH-SB^M（S344K-S346K-L347E-N362S-435DT436（+））进行盐桥网络分析,发现其全局盐桥总数有所下降,但双亚基界面间盐桥数量提高到7个。在重组大肠杆菌中表达了原腈水合酶NHase^M-TH（TH）、盐桥突变酶NHase^M-TH-SB（SB）和盐桥耦合定点突变的重组酶NHase^M-TH-SB^M（SB^M）,研究了3种酶的催化反应动力学和失活动力学。结果表明,SB^M的腈水合酶活性为543.9 U·mg^-1,比TH提高了31.0%;其米氏方程催化速率常数K_cat比TH提高了20%。SB^M的表观失活常数K_D在25～42℃范围内均明显低于对照TH,在42℃时为TH的68.0%,显示了良好的热稳定性。SB^M是活性和稳定性同时提高的重组腈水合酶。