Reverse Micellar Extraction of Lysozyme Using Two Dialkyl Sodium Phosphinates

The extraction of lysozyme was studied using di‐(2,4,4‐trimethylpentyl) sodium phosphinate, R₂POONa, and di‐(2,4,4‐trimethylpentyl) sodium dithiophosphinate, R₂PSSNa. For a R₂POONa reverse micellar system, all lysozyme was removed from the aqueous phase when the pH of the aqueous solution was set below the pI of the protein. The extraction of lysozyme into a R₂PSSNa reverse micellar system was independent of the pH of the aqueous phase. A solubilization limit of lysozyme exists in the R₂POONa reverse micellar phase. The lysozyme recovery was 70% from the R₂POONa reverse micellar phase, and less than 10% from the R₂PSSNa reverse micellar phase.     

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.     

Aggregation Behavior and Micellar Properties of Sodium Salts of Naphthenic Acid Mixtures

The aim of this study was to investigate micellar and self‐assembly properties of four sodium salts of naphthenic acid mixtures by determination and comparative analysis of their critical micelle concentration values at seven different temperatures ranging from 10 to 40 °C using spectrofluorophotometric measurements. It was concluded that fractions having the lowest percentage of aliphatic structures give the least flexible micelles due to sterically rigid structure of cyclic side chains, what makes them difficult to pack in the micellar core. Additionally, surface properties of aqueous solutions of investigated mixtures were studied by the determination of the maximum surface excess, Γ_max and the minimum area per surfactant molecule (A_min) values.     

Modeling and Experimental Data for the Reverse Micellar Extraction of Proteins Using a New Surfactant

ABSTRACT

In this study the reverse micellar extraction of α-chymotrypsin using bis(2,4,4-trimethylpentyl) sodium dithiophosphinate as the surfactant has been investigated. Experiments were performed to determine the effects of pH and salt concentration on the reverse micellar extraction and backward extraction of α-chymotrypsin in isooctane/decanol mixtures. The results showed that both pH and salt concentration influence the reverse micellar extraction of α-chymotrypsin. The pH affects the extraction of the protein through changing the sign and number of the charges carried by protein molecules and thereby affects their interactions with the charged head groups of the surfactant molecules. It was found that at high pH values the hydrogen ions compete with positively charged protein molecules and exchange with the counterions of the surfactant molecules, and as a result destroy the reverse micelles. This effect was exploited for the backward extraction of protein molecules from the reverse micellar phase. A model has been developed to correlate the experimental data of reverse micellar extraction of proteins. In the model the reverse micelles were treated as noninteractive ion-exchange sites. The activity coefficient of the protein molecules in reverse micelles was represented by the model proposed by Pitzer. It has been shown that the model can correlate the experimental data obtained in this work and those reported in other studies.     

Micellization Behavior of Mixtures of Sodium Dioctylsulfosuccinate with Sodium Dodecylsulfate in Water

Mixtures of sodium dioctylsulfosuccinate (AOT) and sodium dodecylsulfate (SDS) that were studied in water at 25 °C by using surface tension, conductance, emf and fluorescence emission methods exhibit synergism in the region where the mole fraction of AOT in the bulk solution (α ₁) is less than 0.7 and ideality in the region where α ₁ ≥ 0.7. The molal conductance versus the concentration behavior of an aqueous solution of AOT is found to be different from that of other ionic surfactants with the exception of bile salts. Composition of the mixed micelle was evaluated and discussed using the Rubingh’s and the Rodenas–Valiente–Villafruela (RVV) treatments. The values of the counter ion binding constant determined from the emf data show that the counter ion binding behavior of the mixed micelle is controlled entirely by AOT. The free energy for mixed micelle formation was calculated using a modified equation. The aggregation number determined by the fluorescence quenching method indicated that in the mixed micelle, as α ₁ increases, the number of molecules of AOT remains constant and that of SDS decreases. Characteristics of the adsorption layer of the mixed surfactant system were also examined using the theoretical treatment of Rosen and Hua.

Preferential Adsorption and Selective Permeation of Alcohol/Hydrocarbon Mixtures in Reverse Osmosis

Abstract

In binary mixtures of alcohols and hydrocarbons there are two types of reverse osmosis performances. These are selective permeation of the alcohol and selective permeation of the hydrocarbon. Liquid chromatography results have been used to predict the selective permeation of reverse osmosis membranes where the membranes may be difficult to fabricate as well as to determine performance limits in terms of separation. These results are of interest for the production of oxygenated fuel blending agents where specifications require the removal of unreacted methanol for further processing and distillation is not viable.     

Extraction of Concanavalin A with Affinity Reversed Micellar Systems

Abstract

An affinity reversed micellar system was used for extraction of concanavalin A (con A) with AOT and a biological detergent as the affinity cosurfactant. Six detergents with varying alkyl tail lengths and different head groups were compared for their extraction efficiency of con A. The effects of system parameters such as solution pH, cosurfactant concentration, and the presence of inhibitory saccharides on protein transfer were studied. For glucosides, protein transfer depends on the tail length of the cosurfactant, and the optimum length for maximum protein transfer is eight. A simple thermodynamic model for affinity partitioning of the protein between the two phases can fit the experimental results reasonably well. The estimated association constants for the protein-cosurfactant complex in the micellar phase are consistent with the literature values. For backward transfer of con A from a micellar phase with a stripping aqueous solution, 12.5% isopropyl alcohol addition to the aqueous phase can release the maximum amount of protein (88%). The reversed micelle still maintained its functional integrity after backward transfer, but loss of cosurfactant to the aqueous phase was significant, and reusability of the micellar phase was rather low. Using a more hydrophobic cosurfactant can only partially solve this problem, where spontaneous loss of cosurfactant to the phase interface during protein backward transfer still occurred.     

Reverse Micellar Extraction of Bromelain from Pineapple (Ananas comosus L. Merryl) Waste: Scale-up,Reverse Micelles Characterization and Mass Transfer Studies

Scale-up studies for phase transfer mode of reverse micellar extraction are attempted for the separation and primary purification of bromelain (EC 3.4.22.33) from pineapple (Ananas comosus L. Merryl) waste. Characterization of reverse micelles and mass transfer studies for the real system has been attempted for the first time. Scale-up of the extraction process employing commercial grade surfactant cetyltrimethylammonium bromide (CTAB) and solvent isooctane resulted in purification of 2.43 fold with an activity recovery 81.3%. The reverse micellar size estimated using empirical and geometrical models indicated that the reverse micelles are large enough (R_m = 7.2–9.6 nm) to host bromelain molecules that are relatively smaller in size (～1.67 nm). The studies on the kinetics of mass transfer indicated a relatively slower rate (by ～34%) of mass transfer in case of back extraction compared to forward extraction. Process scale-up did not significantly affect the extraction efficiency whereas purity of phase components played a major role. The mass transfer across the phases was high in the initial period of mixing for both forward and back extractions.     

Properties of Sodium Methyl Ester Alpha-Sulfo Alkylate/Trimethylammonium Bromide Mixtures

The surface properties of binary mixtures of anionic sodium methyl ester ??-sulfo alkylate (C _m MES) and cationic alkyl trimethylammonium bromide (C _n TAB) of different carbon chain length have been studied in the present work. The critical micelle concentration (CMC) that was obtained from the plots of surface tension (??) versus concentration showed that mixed surfactants have CMC values that were about 10 times lower than their single components. The large negative values for both interaction parameters suggest the existence of strong synergism between the oppositely charged surfactant molecules. The effect of hydrocarbon chain length of either surfactant was also compared and results showed that the effect of cationic surfactant chain length dominated that of the anionic surfactants. It was also discovered that certain mixed surfactant combinations behave differently from the expected trend.     

二烷基乙氧基硫酸钠阴离子双子表面活性剂的合成及其表面活性

为研究阴离子双子表面活性剂结构与表面活性的关系,以不同碳链的脂肪醇、环氧氯丙烷、不同的二醇等为原料,通过三步反应合成出一种间隔基为乙氧基的阴离子双子表面活性剂二烷基硫酸钠,得到不同长度碳链和间隔基的4种双子表面活性剂,同时对部分合成条件进行了优化,确定了烷基单缩水甘油醚所用催化剂为苄基三乙基氯化铵以及烷基低聚二醇的最佳反应温度为80℃。核磁共振氢谱和傅立叶变换红外光谱证实了它们及其中间产品的结构。部分产品最小表面张力低于30 mN/m,临界胶束浓度低于0.1 mmol/L,具有良好的表面活性。实验表明,随着碳链的增长和间隔基长度的增加,其CMC降低,间隔基长度的增加使am in变大,但其γCMC变化不大。     

Micellar Properties for Propoxylated Surfactants in Water/Alcohol Solvent Mixtures and Their Antibacterial and Polyester Fabric Antistatic Performances

Two propoxylated quaternary amine surfactants characterized by two and six average PO adduct numbers (PO-2 and PO-6 QA surfactants) were synthesized to investigate the micellar properties of propoxylated cationic surfactants in water/alcohol mixtures. The effect of PPO groups on micelle formation was explored using conductivity, UV–vis spectroscopy, dynamic light scattering techniques. Regular or reverse micellization occur with water or alcohol rich solvent mixtures, respectively. For intermediate composition no micellization occurs. Also the performances in antibacterial and antistatic fabrics were studied. PO-2 QA surfactant has excellent antibacterial activities against both the Gram-negative bacterium Escherichia coli and the Gram-positive bacterium Staphylococcus aureus while both surfactants have good antistatic activity over polyester fabric.     

Interfacial Dilational Rheology of Sodium Lauryl Glycine and Mixtures with Conventional Surfactants

Amino acid-based surfactants are environmentally friendly surfactants, which have aroused increasing interest. In the application of amino acid-based surfactants, they are often compounded with other kinds of surfactants to obtain formulations that meet certain requirements. Herein, sodium lauroyl glycinate (C12-Gly-Na) was selected as a representative amino acid-based surfactant to compound with an anionic surfactant (sodium dodecyl sulfate [SDS]), a cationic surfactant (dodecyl trimethyl ammonium Bromide), and a nonionic surfactant (Triton X-100: p-octyl polyethylene glycol phenyl ether). Surface tension measurements and interfacial dilational rheological experiments were performed to study the interfacial behaviors of C12-Gly-Na and its mixtures. The results show that mixture systems have better interfacial activity than individual C12-Gly-Na and there is an obvious synergy between C12-Gly-Na and C12TAB under strong electrostatic attraction. Thus, the C12-Gly-Na/C12TAB mixture shows lower critical micelle concentration (CMC) and γ_CMC and higher dilational modulus than the individual surfactants. Besides, the film formed by the C12-Gly-Na/C12TAB mixture has higher viscoelasticity than single C12-Gly-Na and its mixtures with SDS and TX-100. With the increase of bulk concentration, the dilational moduli of C12-Gly-Na, C12-Gly-Na/SDS, and C12-Gly-Na/TX-100 run through two maxima, while, due to stronger electrostatic attraction, only one maximum appears in the C12-Gly-Na/C12TAB system. The study of the interfacial properties of amino acid surfactant and its mixtures with other surfactants provides a theoretical foundation for potential applications in cosmetic, food processing, and daily chemical industries.     

反胶团系统及蛋白质萃取过程研究进展

综述了反胶团系统和蛋白质萃取过程,将反胶团萃取系统按单一反胶团系统、混合反胶团系统和亲和反胶团系统划分,强调了研究开发生物相容性表面活性剂以及在反胶团系统中引入亲和作用的重要性。另外,指出了深入开展反胶团萃取设备和过程研究的必要性。     

牛磺鹅去氧胆酸钠的提取及与鹅去氧胆酸钠的药理作用比较

以500 mL鸡胆汁为基本原料,采用沉淀、过滤、减压蒸馏、真空干燥、抽提、重结晶法,制得了7.2 g结合型的牛磺鹅去氧胆酸钠(TCDCANa),以TLC及IR法确定其结构。并将其与鹅去氧胆酸钠(CDCANa)进行镇咳、平喘和祛痰作用对比实验。药理实验结果为:TCDCANa和CDCANa的镇咳作用减咳率分别为(29.1±5.6)%和(18.2±6.8)%;平喘作用解痉率分别为(79.9±22.8)%和(73.3±22.7)%,祛痰作用酚红排泌量分别为(1.601±0.391)μg/mL和(1.029±0.308)μg/mL,TCDCANa与CDCANa间存在显著性差异(P<0.01)。药理实验结果表明,TCDCANa具有明显的镇咳、平喘、祛痰和抗炎作用,其作用强于CDCANa。     

AOT逆胶束体系脂肪酶催化合成油酸乙酯

在二-(2-乙基己基)琥珀酸酯磺酸钠和异辛烷构建的逆胶束体系中,以Lipex脂肪酶为催化剂,合成了油酸乙酯,考察了各影响因素对其产率的影响,并进行了脂肪酶紫外荧光检测和体系粒度分析. 结果表明,Lipex脂肪酶具有良好的催化活性,反应条件优化选用异辛烷为溶剂,在反应温度25℃、缓冲液pH 6.5、水/表面活性剂(摩尔比)10、乙醇/油酸(摩尔比)20及Lipex脂肪酶浓度0.035 g/L、油酸浓度0.005 mol/L、摇床转速150 r/min、反应36 h的条件下,油酸乙酯产率达到71.25%. 逆胶束粒度和酶构象直接影响酶活性,最适逆胶束粒度约为80 nm.     

Solubilization of Ni Imidazole Complex in Micellar Media of Anionic Surfactants,Sodium Dodecyl Sulfate and Sodium Stearate

The solubilization and physicochemical behavior of a coordination complex of nickel, namely [Ni(im)₆]F₂·5H₂O [hexakis(imidazole)nickel(II) fluoride pentahydrate], in aqueous micellar media of anionic surfactants, i.e., sodium dodecyl sulfate (SDS) and sodium stearate (SS), were investigated by using UV–Vis spectroscopy and electrical conductivity measurements. Spectroscopic techniques were used for the computation of binding constant (K_b), partition coefficient (K_x), change in free energy of binding (ΔG_b), and change in free energy of partition (ΔG_p), whereas electrical conductivity data was helpful to calculate thermodynamic parameters of micellization of surfactants in the presence of the Ni complex, i.e., standard entropy of micellization (ΔS_m), free energy (ΔG_m), and enthalpy of micellization (ΔH_m). It is evident from the results that solubilization of the Ni complex takes place because of electrostatic as well as hydrophobic interactions. The presence of the Ni complex in micellar media increases the critical micelle concentration of both surfactants owing to the structure‐breaking effect.     

Permeabilization of Aspergillus niger by Reverse Micellar Solutions and Simultaneous Purification of Catalase

Abstract

Reverse micellar solutions(RMS) of sodium bis‐ (2‐ethylhexyl)‐sulfosuccinate (AOT) in aliphatic organic solvents were used for permeabilization and protein removal directly from Aspergillus niger cells. Most of the cell wall proteins (～95–100%) were solubilized into the reverse micelles solutions. A significant fraction of intracellular catalase (26–30%) permeates out of the cells and remains on the cell surface and is recovered in a cell wash. Because of it's size the catalase in not solubilized in the RM water pools and thus is not detected in the stripping solution used to recover other proteins from the organic reverse micellar solutions. The remaining amount of catalase is recovered by breaking the cells in purer form. Multiple extractions were used for the extraction of the cell wall proteins followed by ultrasonication of the cells to recover intracellular catalase in a purified form. Therefore, catalase with 5 fold purification was recovered in 88% yield from the RMS‐ treated cells.     

反胶束法制备纳米氧化锌及其在葡萄糖生物传感器中的应用

采用琥珀酸-2-乙基己基磺酸钠/环己烷反胶束体系制备纳米ZnO,并以此ZnO为载体固定葡萄糖氧化酶,用戊二醛交联制作成葡萄糖氧化酶电极. 实验结果表明,此酶电极表现出对葡萄糖溶液浓度的优良响应,线性范围在1′10-5~3′10-3 mol/L,响应灵敏度约为6 mA/(cm2×mmol/L),表观米氏常数为2.57 mmol/L. 还研究了温度和溶液pH值对电极电流响应的影响.     

超临界二氧化碳萃取低挥发性液体混合物的相平衡

在半连续式实验设备中分别测定了苯甲醇－２－苯乙醇和苯甲酸酯－苯甲醇的等摩尔混合物与超临界ＣＯ２三元系相平衡数据。实验温度分别为３０８．２Ｋ和３１８．２Ｋ，压力范围为８～２０ＭＰａ。实验结果表明：对第一个三元系，两种液体在超临界ＣＯ２中的溶解度与ＣＯ２在液相中溶解行为密切相关；对第二个三元系，较高压力下，超临界流体相中苯甲酸甲酯浓度突然增大，而苯甲醇浓度变化不明显。通过引入考虑分子体积差别的二元作用参数，用Ｐｅｎｇ－Ｒｏｂｉｎｓｏｎ方程对气液平衡数据进行了关联。     

Spontaneous Vesicle Formation in Mixtures of Quaternary Ammonium Compounds with Carbamate and Sodium Dodecylbenzene Sulfonate

Spontaneous vesicles formation in the aqueous mixtures of 2,3‐bis (dodecylcarbamoyloxy)‐N, N‐dimethyl‐N‐(2‐hydroxyalkyl) propyl ammonium chloride (C₁₂PAC) and sodium dodecylbenzene sulfonate at different mixing molar ratios have been investigated. The characterizations are demonstrated by electrical conductivity measurements, dynamic light scattering and zeta (ζ) potential measurements. The ζ‐potential results indicate the C₁₂PAC/SDBS systems are stable. The shapes of the catanionic vesicles are observed by negative‐staining transmission electronic microscopy. Meanwhile, from the viewpoint of molecular geometry structure, the electrostatic interaction between anionic and cationic molecules is regarded as the main driving force for spontaneous formation of vesicles.