Single and two-component cation-exchange adsorption of the two pure major whey proteins

Adsorption of pure alpha-lactalbumin (ALA) and beta-lactoglobulin (BLG) to the cation exchanger SP Sepharose FF was studied at pH 3.7 with the purpose of developing a process for isolating them from whey. Measurement of Langmuir parameters describing adsorption equilibrium in batch experiments and protein breakthrough time values in 1-ml packed-beds at a linear velocity of 158 cm/h and initial concentrations of 3 mg/ml for BLG and 1.5 mg/ml for ALA suggested the feasibility of using this adsorbent to separate the two proteins when present in a mixture. Subsequent experiments with 5-ml columns at the above concentrations and a linear velocity of 30 cm/h confirmed this and showed evidence of competitive adsorption as ALA displaced and eluted all BLG from the column in a pure form, and the remaining ALA could be eluted thereafter at high purity and with 91% recovery.