Liu Huizhou

Effects of surfactants on emulsification and secondary structure of lysozyme in aqueous solutions

This paper reports our investigations on the secondary structure of lysozyme in aqueous solution with D2O and comparing systems emulsified with ionic and non-ionic amphiphiles, respectively. The opposite effect of concentration of surfactants on the lysozyme aqueous system was studied and the activity of lysozyme by the turbidimetric assay with different kinds of surfactant was compared. The effect of different surfactants on emulsification volume formed was observed and discussed. The different interactive patterns between lysozyme and ionic and non-ionic surfactants, such as sodium dodecyl sulfate (SDS), cetyl trimethyl ammonium bromide (CTAB) and Triton-X100 (Isooctoylphenoxypolyethoxy ethanol), respectively, was studied with FTIR. A simple relationship between the secondary structure and denaturation of protein is given for the emulsification of lysozyme in aqueous solutions. It is important for understanding the stabilization and avoiding the emulsions in the extraction process that the interactions between the proteins and surfactants which leads to the formation of such complexes are characterized. The utility of surfactants as a de-emulsifying agent for the commercial process to extract penicillin G from the filtrate of fermentation broth was consistent with these results

New mixed solvent systems for the extraction and separation of ferric iron in sulphate solutions

Sulphuric acid is the reagent often used for the leaching of solid materials such as ores and concentrates and iron is usually present in the leach solution as an impurity. The most difficult problem associated with the solvents that have been studied for iron removal in sulphate solution is the stripping of iron from the organic phase. Several mixed solvent systems for iron removal were developed in this work. These solvents have the common feature that iron extracted into the organic phase can be stripped with dilute sulphuric acid. The extraction and stripping for some of the mixed solvent systems have been studied and a mechanism is proposed.