Thermodynamic adsorption properties of bovine serum albumin and lysozyme on the bubble surface from the binary solution

In this work, the thermodynamic adsorption properties of bovine serum albumin (BSA) and lysozyme (LZM) on the bubble surface from the binary solution were studied to promote the application of foam fractionation in the selective separation and purification of proteins. The thermodynamic adsorption properties included the adsorption isotherm, the distribution coefficient and the separation factor. Redlich-Peterson equation could be effectively used to describe the equilibrium adsorption of BSA and LZM on the bubble surface from the binary solution. Under the conditions of temperature 30 °C and pH 4.6, the adsorption isotherms of BSA and LZM were Γ1 = 3.12 × 10−1C1/(1 + 61.70C10.75 + 0.18C20.93) and Γ2 = 5.30 × 10−2C2/(1 + 61.70C10.75 + 0.18C20.93), respectively. According to the adsorption isotherms, the BSA concentration had significant effects on the distribution coefficient of LZM, but the LZM concentration had almost no effects on the distribution coefficient of BSA. The separation factor of BSA to LZM was a constant, 5.89, and was irrelative to the BSA and LZM concentrations. The absorption of BSA and LZM on the bubble surface was heterogeneous because of their different molecular sizes and charges.