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 H ₂SO ₄ in the presence of P ₂O ₅. The sulfonic acid groups (4.8mmol/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. 16μm) 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, 1.0g/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.