Acrylic Acid-grafted Fibers Enable High-capacity Binding of Lysozyme Dissolved in High-concentration Phosphate Buffer

Abstract

To prepare a weakly acidic cation-exchange fiber capable of binding lysozyme dissolved in a high-concentration phosphate buffer, acrylic acid (AA) was graft-polymerized onto a nylon-6 fiber by radiation-induced graft polymerization. The dynamic binding capacity (DBC) of the bed charged with the AA-grafted fiber at a space velocity of 20 h⁻¹ was determined in a flow-through mode for lysozyme solutions buffered with 50–250 mM phosphate solution (pH 6.0). The DBC of the CM-Sepharose-FF-bead-packed column decreased from 88 to 9 mg/mL-bed with increasing buffer concentration. In contrast the AA-grafted-fiber-packed column exhibited a constant value of 200 mg/mL-bed independent of the buffer concentration from 50 to 200 mM.