A method for fabrication of polyaniline coated polymer microspheres and its application for cellulase immobilization

Poly(styrene-divinylbenzene) (PS-DVB) microspheres were grafted with polystyrene (PS) via surface initiated-atom transfer radical polymerization (SI-ATRP). The grafted PS chains were sulfonated with H2SO4 in the presence of P2O5. The sulfonic acid groups (4.8 mmol/g) on the surface brushes were neutralized with aniline, and the adsorbed aniline was polymerized by oxidizing with potassium persulfate to give self-doped and thick PANI layers (i.e. 16 μm) on the microspheres. Then, cellulase was immobilized on the polyaniline (PANI) coated PS-DVB-g-PS microspheres via adsorption and adsorption/cross-linking methods. The properties of the immobilized cellulase preparations were investigated and compared with those of the free enzyme. After immobilization, the recovered activities of the adsorbed and adsorbed/cross-linked cellulase were found to be 73 and 62% for the substrate, carboxymethyl cellulose (CMC, 1.0 g/L), respectively. The immobilized enzyme preparations had better stabilities and higher retained activities with respect to pH, temperature and storage stability than those of the free enzyme.

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► Polyaniline grafted polystyrene microspheres was used for immobilization of cellulase.
► FTIR and SEM studies confirmed surface modification of microspheres.
► The enzyme was immobilized on the supports via adsorption and adsorption/cross-linking.
► Immobilized cellulase was used for hydrolysis of CMC starch.
► Operational, thermal, and storage stabilities of cellulase were enhanced upon immobilization.