Continuous forward and back extraction of lysozyme from egg white using reverse micelles

Gentle mixing characteristics in a Graesser contactor can avoid the formati on of stable emulsions, and this is one advantage of this contactor when us ed with reversed micellar extractions. However, this characteristic of the contactor is a disadvantage for back extraction using the conventional meth od (extremes in pH and ionic strength) because it gives a low extraction yi eld and requires a larger contactor. In order to develop an integrated proc ess for continuous protein separation using reverse micelles, this work foc used on assessing the novel technique of back extraction using a counterion ic surfactant in a mixer-settler. It was found that the process gave a high extraction yield (95-100%) within an extraction time of only 5 min. Lower mixing speeds (200 rpm) and pHs (6) resulted in the highest sedimentation r ate in the organic phase. Unfortunately, the cloudiness of the aqueous phas e and the slow rate of lysozyme transfer into the aqueous phase in the sett ler were potential drawbacks of the system. However, the use of centrifugal force was found to be an important factor in enhancing the rate of back ex traction when using a counterionic surfactant. Based on previous work of ou rs on forward extraction in a Graesser contactor, the continuous separation and recovery of proteins using reverse micelles seems feasible.