Effect of temperature on the reversed micellar extraction of enzymes

In “conventional” liquid-liquid extraction of protein solutions with a reversed micellar phase, the protein is transferred from an aqueous phase to the reversed micellar phase by forward extraction, and subsequently to a second aqueous phase during back extraction. This back transfer is a relatively slow process, owing to a large interfacial resistance to mass transfer. In this paper an alternative procedure is described for the back extraction, using the effect of temperature. By increasing the temperature of the reversed micellar phase, after it has been saturated with the aqueous phase during the forward extraction, a separate aqueous phase is formed in which most of the enzyme is concentrated. This excess aqueous phase can be separated easily from the reversed micellar phase by centrifugation. The enzyme can be recovered in this expelled phase at extremely high concentrations (up to 2000 times the initial concentration). This process has been performed continuously using two centrifugal separators, with the reversed micellar phase circulating between the two units. For α-amylase a recovery rate of 73% of the enzyme activity was achieved.