Formation of reverse micelles with dialkyl sodium phosphinates and their use for extraction of amino acids

Experiments were performed to determine the ability of three anionic surfactants for the formation of reverse micelles and the reverse micellar extraction of L-lysine. The surfactants studied 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). The effects of the concentration of salt, nature and concentration of surfactant and alcohol cosurfactants, on the formation of reverse micelles were studied comparatively. For the reverse micellar extraction of L-lysine, the effect of nature of the surfactant, pH and salt concentration were also comparatively studied. Since all three surfactants have two identical tails and differ in their polar heads their comparative study gives an insight into the effect of the surfactant head in the formation of reverse micelles and the reverse micellar extraction of biomolecules.The results show that, under well defined conditions, these surfactants can form reverse micelles and have the ability to extract L-lysine. They have a clear advantage over other surfactants for the back-extraction and concentration of amino acids into a new aqueous solution free of surfactant