Membrane Separation Followed by Ion Exchange Chromatography for Preparation of High-Purity α-Lactalbumin

In this study, ion exchange chromatography was employed to prepare high-purity α-lactalbumin from whey protein powder obtained from raw cow’s milk by sequential membrane separation and spray drying. The results showed that α-lactalbumin constituted 21.04% of the true protein in the permeate obtained using a 50-nm pore-sized ceramic membrane with three-fold concentration, one cycle of microfiltration and two cycles of washing, which was higher than that obtained using a 100-nm pore-sized ceramic membrane (15.84%). The permeate was spray dried and separated by ion exchange chromatography. Good chromatographic separation of α-lactalbumin and β-lactoglobulin was achieved with increasing NaCl concentration from 0 to 0.5 mol/L at up to 10 column volumes, and 98.18% pure α-lactalbumin and 97.82% pure β-lactoglobulin were obtained. The results of this study provide support for the industrial preparation of high-purity α-lactalbumin.