Enhancing oxidation activity and stability of iso-1-cytochrome c and chloroperoxidase by immobilization in nanostructured supports

The immobilization of enzymes in inorganic materials has been widely used because it can produce an enhancement of the catalytic stability and enzymatic activity. In this article, the effect of the immobilization of iso-1-cytochrome c (CYC-Sc) from Saccharomyces cerevisiae and chloroperoxidase (CPO) from Caldariomyces fumago on the enzyme stability and catalytic oxidation of styrene was studied. The immobilization was carried out in three silica nanostructured supports with different pore size MCM-41 (3.3 nm), SBA-15 (6.4 nm) and MCF (12.1 nm). The adsorption parameters and leaching degree of immobilized enzymes were determined. Catalytic parameters of immobilized and free enzymes were determined at different temperatures (20-60 degrees C) and in different acetonitrile/water mixtures (15-85% of acetonitrile). The results show that there is low leaching of the enzymes in the three supports assayed and the adsorption capacity (q(max)) was higher as the pore size of the support increased. The pore size also produces the enhancement of peroxidase activities on the styrene oxidation. Thus, CPO adsorption into SBA-15 and MCF showed remarkable thermal and solvent stabilities at 40 degrees C showing a total turnover numbers of 48,000 and 54,000 times higher than free CPO, respectively. The enhancement of activity and stability doubtless is interesting for the potential industrial use of peroxidases. (C) 2011 Elsevier B.V. All rights reserved.