Synthesis and properties of a novel crosslinked chitosan resin modified by l-lysine

This paper reported the synthesis and properties of a novel crosslinked chitosan resin modified by l-lysine (LMCCR). The new chitosan derivative that produced through the reaction between glutaraldehyde semi-crosslinked chitosan and l-lysine, could be considered either as a reactive and functional polymer or a macroporous weak anion exchanger. The chemical structure characterizations of LMCCR performed by FTIR, 13C NMR and X-ray diffractometry illustrated that amino groups in chitosan had participated in the formations of both the Schiff bases (NC) and the acylated side-chains during the synthesis. The micrography and SEM analysis showed that the LMCCR beads were spherical and porous, with a bead size of 800-1000 μm diameter. LMCCR was found to swell rather than dissolved in acidic mediums from its solubility and swelling behaviors experiments. LMCCR showed considerable adsorption properties as a macroporous weak anion exchanger, with the adsorption capacity of 409.24 mg/g, 253.28 mg/g, 59.52 mg/g and 204.12 mg/g for acetic acid, alanine, BSA and Zn2+, respectively. The immobilized glucose oxidase that immobilized by LMCCR through covalent bonds exhibited a retentive activity of 42.68% and a half-life of 96 days, showing the LMCCR's good performances and potential applications in enzyme immobilization.