Immobilization of endopectinlyase on g-alumina: study of factors influencing biocatalytic matrix stability

Endopectinlyase (EC 4.2.2.10) from Aspergillus japonicus was immobilized on to gamma-alumina. Adsorption performed at pH 5.0 and a subsequent cross-linking phase using 0.1% glutaraldehyde were the chosen immobilization conditions. The comparison between the main biochemical parameters of the immobilized and free form of the enzyme showed that the immobilization procedure used did not affect the enzyme biochemical properties. The interactions between the carrier and the enzyme are essentially secondary bonding. In fact they depend on the pH and on the presence of phosphate ions in the medium. A tentative chemical model of the biocatalytic matrix thus obtained is proposed.