Functionalized electrospun nanofibers from poly (AN-co-MMA) for enzyme immobilization

beta-Galactosidase from Aspergillus oryzae was immobilized on amino functionalized poly (Acrylonitrile-co-Methyl methacrylate) poly (AN-co-MMA) nanofibers using glutaraldehyde. Among the four different factor used for activation, the activation of poly (AN-co-MMA) nanofibers by glutaraldehyde followed by covalent enzyme on activated support could stabilize the enzyme beta-galactosidase and was found to be effective. Different factors affecting the activation process were investigated and their impact on the activity and the retention of immobilized enzyme's activity was monitored. Concentration of glutaraldehyde and activation temperature, time, and activation pH were found of a determined effect. The optimum concentration, reaction time, reaction temperatures, and activation pH value of glutaraldehyde are 5.0, 180 min, 65 degrees C and 11.0, respectively. The scanning electron micrographs showed the change on the poly (AN-co-MMA) nanofibers surface revealing the successful immobilization of beta-galactosidase. Thermal and pH stabilities were found to be increased upon immobilization. The immobilized beta-galactosidase had better resistance to temperature and pH inactivation than did the free form. Finally, the immobilized beta-galactosidase retained 35% of its initial activity when stored at 4 degrees C for 70 days and retained 64% of its initial activity after ten consecutive reactor batch cycles. (C) 2012 Elsevier B.V. All rights reserved.