Implications from γ-globulin adsorption onto cation exchangers fabricated by sequential alginate grafting and sulfonation

Abstract

Abstract Our previous work proved that high adsorption capacity and uptake rate of lysozyme were achieved on alginate (Alg)-grafted resin with an ionic capacity (IC) of 240 mmol·L−1 (Alg-FF-240). Moreover, the salt-tolerant feature of Alg-FF-230 was improved by using sequential alginate grafting and sulfonation strategy. Inspired by the enhanced adsorption performance of lysozyme, we have herein proposed to investigate the static and dynamic adsorption behaviors of γ-globulin on a series of Alg-grafted resins with different grafting densities and sulfonation degrees. The adsorption capacity of γ-globulin decreased with increasing alginate-grafting density (IC) from 160 to 230 mmol·L−1 at 0 mmol·L−1 NaCl because of the steric hindrance caused by the alginate-grafting layer. Effects of ionic strength (IS) indicated that the adsorption capacities of the resins with the IC value of 230–370 mmol·L−1 were much higher than CM Sepharose FF at 50–100 mmol·L−1 NaCl, and the uptake rate of Alg-FF-230 was about twice as much as that of CM Sepharose FF. This work demonstrated the important effects of alginate-grafting layer and IS in γ-globulin adsorption behavior, which would be helpful in the design of Alg-grafted resins and the selection of proper IS condition for protein purification.