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 mu m) 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. (C) 2012 Elsevier B.V. All rights reserved.