The paper deals with the pectolytic enzymes immobilization on different acrylic supports, and the application of immobilized preparations in the apple juice pectinization process. The correlation between the protein content (C,) and specific catalytic activities of immobilized enyzme preparations suggest a specific immobilization process only in the case of PONILEX ASH type acrylic supports. The active immobilization degree on PONILEX ASH type supports of Ultrazym 100 G and technical pectinase extract ranged from 99.80 to 296.40% for the Pectinesterase (PE) activity, and from 101.85 to 752.94% for the chain splitting (CS) activity, proving that the ionic immobilization process is a selective one. The simulated operational stability of the immobilized pectolytic enzymes tested by the PE and CS activity values proves the preservation of enzyme catalytic activity.Acta Biotechnologica 12 (1992) 6 functional groups, total exchange capacity of 0.50 meq . ml-' and 2.07 meq . g-'; 0.48 meqml-' and 1.65 meq . g-', respectively; PONILEX CC-31, carboxylic functional groups, total exchange capacity of 1.44 meq . ml-' and 12.27 meq . g-'); Ultrazym 100 G (U, E.C. 3.1.5.11 and E.C. 3.2.1.15) produced by NOVO Co.; technical pectinases extract (TPE, E.C. 3.1.1.11 and E. C. 3.2.1.15) produced by the Biological Research Centre (BRC) Jassy; amyloglucosidase (AG, E. C. 3.2.1.3) produced by the Food Research Institute (FRI) -Bucharest; cellulases (C, E.C. 3.2.1.4) produced by the Chemical and Biochemical Energy Institute (CBEI) -Bucharest; pectin (average content of esteric groups = 70 per cent); carboxymethylcellulose; Watmann filter paper; cellobiose; maltodextrine; juice from different types of apples, some fresh, and some with different storage periods; 0.02m and 0.20m acetic acid-Natrium acetate buffer solution; pH = 4.5; 0.1 N Natrium hydroxide solution.
