Immobilization of cellulase enzyme on superparamagnetic nanoparticles and determination of its activity and stability

Cellulase on commercial superparamagnetic nanoparticles was characterized by DLS, and TEM methods in relation to their size and structure. The cellulase enzyme was bound via physical adsorption (ionic bound). FTIR spectroscopy confirmed the successful binding of cellulase (endoglucanase) onto the particle, and binding efficiency was determined at 95% using the Bradford method. The maximal enzyme activity was assessed using CMC as the substrate and was 0.1 unit (mu mol/min ml). The adsorption capacity of cellulase onto nanoparticles reached 31 mg/g. The stability of the immobilized enzyme increased in comparison with the free enzyme. Overall, this study showed that that the stability and activity of the cellulase were enhanced via physical adsorption to the magnetic nanoparticles. This suggested that immobilized enzyme on magnetic beads could be used in an interesting range of application allowing both using in broader temperature and pH ranges, facilitating long-term storage, while permitting magnetic recovery of the enzyme for reuse or purification of the product. (C) 2011 Elsevier B.V. All rights reserved.