AOT反胶束萃取胰蛋白酶的STM及主要影响因素

In this article, the influence factors of trypsin extracted from crude pancreatin was investigated, and scanning tunneling microscope(STM) was used to observe the image of trypsin in butane-diacid-2-ethyl-hexyl-ester-sulfonic sodium (AOT)/iso-octane reversed micelles. The STM image showed that trypsins bounded in reversed micelles was rigid, which weakened its conjugative effect and caused maximum ultraviolet absorption and fluorescence emissive absorption moving toward blue waves. AOT concentration, pH and cations were the main influence factors of extraction. Specifically, extraction percentage of trypsin decreased with the increase of AOT concentration from 0.01 to 0.1mol·L-1. When pH value is from 5.30 to 10.0, i.e. less than pI of trypsin, the extraction percentage is raised with the different increase of pI-pH, but when the pH value is less than 5.20, the extraction percentage is decreased with the acidity added. Besides, the extraction efficiency is negative, related with the concentrations of Ca2 , Na ,K which were in the range of 0.2-1.0mol· L-1, and influence of concentration of Ca2 is greater than that of Na , and K which has the minimum impact with the same concentration. Finally, optimum conditions to extract trypsin were: AOT reversed micelles 0.05mol·L-1, trypsin concentration in crude pancreatin solution 3mg·ml-1, pH 5.2- 5.3, ratio (by volume) of extraction phase to strip-extraction phase 1:1, and time of 5min. The corresponding percentage of extraction was 22.7% and specific activity was 78.9 N-benzoyl-L-arginine ethyl ester (BAEE) U·mg-1 protein, three times than that in crude pancreatin. There was no lipase and amylopsin activity was decreased to 1/5 of crude pancreatin. Partly purifying solution was treated by condition mentioned above with 0.05mol·L-1 ceryl-trimethyl-ammonium bromide (CTAB), total extraction percentage of trypsin was 74.18% and specific activity was 3148.3 BAEE U·mg-1, i.e. 48.16 times purer than that in crude pancreatin. Through sodium dodecyl sulfate-polyacryl amide gel electrophoresis (SDS-PAGE) and image analysis of extracted product, there were only three bands in the trypsin, while seven in crude pancreatin, and electrophoresis location of main bend was almost identical with the standard enzyme.     

反胶束中中性蛋白酶AS1.398反应机理

枯草杆菌中性蛋白酶AS1.398可用于反胶束萃取全脂豆粉分离大豆蛋白和油脂.揭示酶的催化作用机理可用于优化萃取条件.以大豆分离蛋白为底物,研究了AS1.398在AOT/异辛烷反胶束体系中的反应机理. 由于底物分子在反胶束中呈泊松分布,通过计算底物和酶分子数比例,推算出酶催化为单底物反应的概率占绝对优势.借鉴水相酶反应模型,考虑反胶束中分子交换作用,提出了反胶束中酶的单底物分子反应的作用模型,模型推导出水相的米氏常数比反胶束相的大1个数量级.实验测定酶在水相和反胶束相的米氏常数分别为3.2×10^-3g•ml^-1和4.2×10^-4g•ml^-1.两者比值与模型推导出的关系较吻合,表明此模型可用来表示反胶束中AS1.398的催化反应.     

SEPES/异辛烷反胶团中脂肪酶的特性

<正>反胶团酶反应兼有水相与有机相酶反应的共同优点,但至今尚无工业应用的重要原因是反胶团中酶的活性和稳定性不高.常用的离子型表面活性剂,如二-(2-乙基己基)琥珀酸双酯磺酸钠(AOT)在有机溶剂中形成的反胶团,因相界面与酶分子间的静电作用将造成酶在反胶团中迅速失活.而非离子型表面活性剂形成的反胶团中,酶一般具有较高的活性和稳定性,但这种体系需加入助表面活性剂,给下游加工过程带来麻烦.作者制备了具有不同氧乙烯聚合数(n)的二-(2-乙基己基聚氧乙烯)琥珀酸双酯磺酸钠(简称SEPES),其分子结构与AOT相似,但其极性头与疏水尾间连有聚氧乙烯链非离子性亲水基团.本文报道脂肪酶在SEPES/异辛烷反胶团体系中的特性.     

气溶胶OT反胶束对L-胱氨酸的萃取行为研究

实验考察了气溶胶OT (AOT即 2 乙基己基琥珀酸酯磺酸钠 )浓度、盐酸浓度、L 胱氨酸浓度、无机盐浓度及温度对AOT反胶束萃取L 胱氨酸的影响。结果表明 :AOT浓度增大萃取分配系数增大 ;水相中盐酸浓度增大、无机盐浓度增大、胱氨酸初始浓度增大均使萃取分配系数降低 ;萃取温度升高使萃取的分配系数减小 ,说明AOT反胶束萃取胱氨酸是一个放热过程 ,低温有利于胱氨酸的萃取     

OP-7/氯仿反胶束体系的制备及其增溶水量的研究

以氯仿代替传统的烃类溶剂,制备新型OP-7(非离子表面活性剂)/氯仿反胶束体系,并对该体系的增溶行为进行研究。考察了OP-7的浓度和不同的助表面活性剂对该体系增溶水量的影响及增溶水量与体系的粒径、电导率的关系。结果表明,OP-7的浓度、助表面活性剂醇的种类和用量都影响着体系的增溶水量;同时增溶水量增加,体系的粒径和电导率随之增加,OP-7/正辛醇/氯仿反胶束体系增溶水量最大。     

反胶束体系中固定化胃蛋白酶的催化性质研究

将胃蛋白酶加至CTAB(十六烷基三甲基溴化铵)/环己烷/正辛醇反胶束体系中得到固定化胃蛋白酶,研究了反胶束含水率、乙醇体积分数对固定化胃蛋白酶活力的影响,并对固定化胃蛋白酶和游离胃蛋白酶的催化性质进行了比较研究.结果表明,反胶束含水率为12％、乙醇体积分数为30％时,固定化胃蛋白酶的活力达到最佳;固定化胃蛋白酶和游离胃...     

反胶束体系对甲基橙废水处理效果的研究

以正戊醇和阳离子表面活性剂十六烷基三甲基溴化铵(HTAB)形成的反胶束体系对甲基橙(MO)的去除效果进行研究。同时分析了反应时间,HTAB浓度、pH值和离子强度及种类对去除率的影响。实验发现,反应时间为5 min即可达到平衡;最佳HTAB浓度为0.5 g/L;碱性环境有利于甲基橙的去除;离子强度过高时严重抑制MO的去除,改变阴离子种类对去除率有显著影响。     

Ag/Co/Au三金属纳米粒子的合成及表征

反胶束是指由介于油和水界面的表面活性剂分子来稳定的,且均匀分散于连续油介质中的微液滴,由于微液滴的尺寸限制和其在油介质中的良好分散性,它可以作为"微反应器"合成纳米材料。以AOT为阴离子表面活性剂,采用反胶束法合成了Ag/Co/Au纳米粒子。采用紫外-可见(UV-Vis)吸收光谱、傅立叶红外光谱(FT-IR)对产物进行表征。研究结果表明,反胶束法合成Ag/Co/Au纳米粒子粒径均匀,分散性好、稳定性好。     

SDSS-D2EHPA/异辛烷混合反胶团体系萃取细胞色素C

用SDSS－D2EHPA／异辛烷混合反胶团体系提取蛋白酶细胞色素C,研究了水相pH值、离子强度、SDSS浓度、提取时间等对提取率的影响,结果表明,提取率可达100％,并且提取条件温和、简便,可在中性介质和室温下进行,提取量大,提取时间短,5min即可完成。     

反胶束萃取蛋白质技术的新进展

本文综述了近年来反胶束萃取蛋白质这一技术在基础理论研究、应用和过程开发三方面所取得的新进展，指出了某些不足之处，并对今后的研究工作提出了建议。     

反胶束体系中水团的笼效应

在反胶束体系中研究了菁染料的吸收光谱以及ω值对菁染料荧光光谱的影响．讨论了不同粒径的AgCl纳米粒子对反胶束体系中菁染料的吸附状态及J-聚集体形成的影响．特别研究了反胶束水团空间限定效应对菁染料荧光量子产率及J-聚集体的影响。     

Forward and Backward Extraction of Methylene Blue by using AOT/Isooctane Reversed Micellar Solution

Organic dyes, which are contained in industrial effluents, should be removed to avoid health hazards and destruction of the ecosystem. In this study, the extraction of methylene blue from aqueous solution into AOT/isooctane reversed micellar solution was investigated. It was found that methylene blue was solubilized into the waterpool within reversed micelles by electrostatic interaction with AOT. The extraction ratio of methylene blue increased with an increase in AOT concentration and a decrease in salt concentration. The methylene blue extracted reversed micelles could be recovered into fresh salt solution with high concentration. It is considered that the main driving force of forward and backward extraction of methylene blue is electrostatic interaction between cationic dye, methylene blue, and anionic surfactant, AOT. The deterioration of the forward and backward extraction behavior by using AOT/isooctane reversed micellar solution reused was not observed.     

Purification of the Penicillium citrinum Lipase Using AOT Reversed Micelles

This work describes the extraction and back-extraction of a lipase from crude extract of Penicillium citrinum using AOT reversed micelles in isooctane. The effect of pH, ionic strength, AOT concentration on the protein forward and backward transfer at 20°C was studied. The maximum protein forward extraction (32·0%) was achieved at pH 4·0 with a 50 mmol dm⁻³ acetate buffer containing 100 mmol dm⁻³ KCl and 100 mmol dm⁻³ AOT in isooctane. Proteins were back-extracted (82·7%) to a new aqueous phase containing 100 mmol dm⁻³ pH 8·0 phosphate buffer and 1000 mmol dm⁻³ KCl. No enzyme activity could be detected either in the micellar phase or in the aqueous phase after protein back-extraction. However, the lipolytic activity was recovered after hydrophobic interaction chromatography on a Phenyl Superose column. The yield obtained for the overall process was 68% for activity, 26·4% for protein recovery and the purification factor was 810-fold. A single protein band at 33000 Da was obtained for SDS–PAGE analysis for the recovered and purified enzyme. © 1997 SCI.     

超临界CO2体系中的反胶团

本文对超临界CO2反胶团技术的发展状况,包括基本原理,研究方法,应用领域,发展趋势和和了全面阐述。     

反胶团酶催化反应动力学

本文将反胶团酶催化反应动力学分为拟相模型、胶团动力学模型和底物吸附模型三大类 ,扼要介绍了每一类的研究现状并探讨了今后的研究方向     

反胶团技术应用研究进展

反胶团具有独特的优良性能,有着十分广阔的应用前景,近年来正越来越多地受到关注。该文介绍了反胶团理论的最新研究进展,综述了反胶团技术在酶催化反应、萃取分离、纳米粒子的制备等方面的应用研究进展, 提出了反胶团技术目前存在的问题,并对其应用前景作了展望。引用文献22篇。     

Cadmium Sulfide Aggregates through Reverse Micelles

CdS aggregates, composed of primary nanocrystalline particles, were synthesized in cyclohexane-sorbitan monooleate (Span 80) reverse micelles at 80°± 1°C under mechanical agitation and sonication with varying Cd²⁺ concentrations in the solutions. The critical micelle concentration (CMC) of the surfactant Span 80 in cyclohexane was determined from discernible breaks in the surface tension and optical (ultraviolet) absorbance versus surfactant concentration curves. The synthesized aggregates were characterized using transmission electron microscopy, X-ray diffractometry, particle-size analysis, Fourier-transform infrared spectroscopy, and thermal analyses. The generated aggregates exhibited the characteristic green emission at 520 nm. A minor decrease in emission intensity with increased aggregate size at the same wavelength was observed.     

Reverse Micellar Extraction and Backextraction of l-Lysine with Three Dialkyl Sodium Phosphinates in Pentanol/Isooctane Mixtures

Abstract

The effects of pH, salt concentration, and structure of the surfactant head on the reverse micellar extraction and backextraction of l-lysine in pentanol/isooctane mixtures have been comparatively studied. The surfactants used were bis(2,4,4-trimethylpentyl) sodium phosphinate (NaPOO), bis(2,4,4-trimethylpentyl) sodium monothiophosphinate (NaPSO), and bis(2,4,4-trimethylpentyl) sodium dithiophosphinate (NaPSS). Since all three surfactants have the same two hydrocarbon tails and differ only in their polar heads, their comparative study gives some insight into the effect of the surfactant head group on the reverse micellar extraction and backextraction of amino acids. The results show that the nature of the surfactant head, the pH, and the salt concentration have a major effect on the reverse micellar extraction of l-lysine. The percent of l-lysine extracted to the organic phase, at fixed surfactant and pentanol concentrations, decreased in the order NaPSS > NaPSO > NaPOO. The exchange with the three surfactants can be easily reversed for the backextraction of amino acids into a new surfactantfree aqueous solution.