Development of superparamagnetic functional carriers and application for affinity separation of subtilisin Carlsberg

Superparamagnetic functional carriers to obtain high selectivity were reported in this study. Magnetic carriers with epoxy groups were synthesized by spraying suspension polymerization (SSP). The measurement of scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) showed that the magnetic carriers have a narrow size distribution and displayed superparamagnetic characteristics. The magnetic carriers with epoxy groups were modified by various affinity ligands to magnetic functional carriers such as copper-IDA carriers, benzamidine carriers and phenylboronic acid carriers. The effects of medium pH and subtilisin Carlsberg concentration on adsorption capacity were investigated. It was found that phenylboronic acid and benzamidine immobilized magnetic carriers were effective magnetic carriers for affinity adsorption of subtilisin Carlsberg, and the maximum adsorption capacity (about 65 mg/g) was obtained at pH 9.5. The adsorbed subtilisin Carlsberg was also desorbed successfully by using dissociation agents, and the recovery of the enzyme activity was still around 85%.