A REVERSED MICELLAR SYSTEM USING MIXED SURFACTANTS OF SODIUM BIS (2-ETHYLHEXYL) SULFOSUCCINATE AND DI(2-ETHYLHEXYL) PHOSPHORIC-ACID FOR EXTRACTION OF PROTEINS

Protein extraction, including solubilization of water, in a reversed micellar solution has been studied using mixed surfactants of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) and di(2-ethylhexyl) phosphoric acid (DEHPA) in isooctane. It appears that the mixed micelles could be formed from AOT and charged species of DEHPA molecules in the organic phase, while uncharged DEHPA does not take part in forming the micelles. The solubilization of water into the mixed micelles depends on pH and salt concentration in the aqueous solution as well as composition and concentration of surfactants. Hemoglobin having relatively large molecular weight could be successfully extracted by the mixed micelles. Furthermore, it was found that the addition of n-hexanol in the micellar solution is useful for stripping of proteins from the micelles into dilute alkaline solution.