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Most applications of surfactants depend on formation and characteristics of micelle. In this study we measured critical micelle concentration (CMC) of cationic surfactant N, N', N'-polyethylene (10)-N tallow-1, 3-di amine propane (PEG-10 tallow) in aqua solution by using electrical conductivity and surface tension methods. The CMC value of PEG-10 tallow with two different methods was found very close to 1.40 × 10 −3 M with electrical conductivity, and 1.41 × 10 −3 M with surface tension. It also investigated the effect of inorganic salt (NaCl) and pH on micellization of cationic surfactant PEG-10 tallow. With increasing addition of NaCl, formation of micelle structure resulted in a higher CMC. However, at low salt concentrations smaller CMC value was observed comparing the critical micelle concentration of individual PEG-10 tallow. When it comes to the effect of changing pH in CMC of the PEG-10 tallow , it was clearly found that micelle formation or CMC of surfactant was independent on alkaline pH (between 6 and 10), but it was dependent on acidic pH (below 5).

The aim of the present study was the selective precipitation of plasmid directly from alkaline lysate produced from bacterial culture with the cationic detergent, N, N', N'‐polyethylene (10)‐N tallow‐1, 3‐di amine propane. Polyethylene groups of peg‐10 tallow were functionalized with tertiary amine groups and long alkyl chain. The functional groups of cationic detergent were determined by means of 1H nuclear magnetic resonance (NMR) spectroscopy. A simple and efficient process for plasmid purification by cationic detergent was found to be dependent on acid concentration. The structure of peg‐10 tallow cationic detergent after adding acid solution was characterized using Fourier transform infrared (FT‐IR) spectroscopy. Inorganic acid such as HCl was introduced into the solution of peg‐10 tallow. Controlling pH of precipitation system by the addition of different concentrations of HCl acid solutions on peg‐10 tallow improved the partial separation of RNA from plasmid DNA (pDNA). However, different lysate masses were applied to observe the effect of 7.5% acid solution on the separation of RNA from pDNA with a peg‐10 tallow cationic surfactant. The results were realized by 1% agarose gel analysis. Copyright © 2009 John Wiley & Sons, Ltd.

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L-glutaminase enzyme produced from Hypocrea jecorina pure culture and polyacrylic acid (PAA) in the presence (Cu2+) ions were composed the ternary complex at pH 7. The properties of free and immobilized enzyme were defined. The effect of various factors such as pH, temperature, heat, and storage stability on immobilized enzyme were investigated. The properties of immobilized enzyme were investigated and compared to those of free enzyme. Optimum pH and temperature of both enzyme were determined to be 8.0 and 50°C, respectively. Kinetic parameters of the immobilized enzyme (Km and Vmax values) were also determined as 0.38 mM of the Km and 10.9 U/L of the Vmax. No drastic change was observed in the Km and Vmax values. Thermal and storage stability experiments were carried out. The thermal stability studies indicated that the immobilization process tends to stabilize the enzyme.