Ginsenoside CK production by commercial snailase immobilized onto carboxylated chitosan-coated magnetic nanoparticles

Immobilization of glycosidases for ginsenoside CK production is a promising method to improve industrial production. Magnetite (Fe3O4) nanoparticles encapsulated with carboxylated chitosan (CYCTS) (Fe3O4@CYCTS) provide a large specific surface area for snailase immobilization. According to the morphology, structure, and magnetic properties determined by TEM, SEM, XRD, FTIR, and VSM, the spherical, 50-nm Fe3O4@CYCTS nanoparticles were synthesized and applied for the first time in snailase immobilization. The immobilized enzyme (Fe3O4@(CYCTS+Snailase)) could be easily separated from the reaction mixture using a simple magnet. Under optimum immobilization conditions (37 ℃, pH 5.5, 5 h), the protein adsorption on the surface of Fe3O4@CYCTS was mainly driven by electrostatic interactions and exhibited a maximum value of 67.67 mg enzyme/g of support. The storage stability of immobilized enzyme and the stability against thermal, pH, or chemical denaturants were improved. The immobilized snailase shows a higher affinity toward substrates as indicated by lower Km values. At optimum reaction conditions (55 ℃, pH 5.5, 48 h), the immobilized snailase retained approximately 56% of its initial catalytic activity over 9 successive cycles. Our results revealed the potential applicability of Fe3O4@(CYCTS+Snailase) in ginsenoside transformation.