PECTOLYTIC ENZYMES COIMMOBILIZATION ON GAMMA-ALUMINA SPHERES VIA ORGANOPHOSPHATE COMPOUNDS

Endopectinlyase (EC 4.2.2.10), endopolygalacturonase (EC 3.2.1.15) and pectinesterase (EC 3.1.1.11) present in a commercial mixture were co- immobilized on gamma-alumina spheres activated with organophosphate co mpounds. Staining of the alumina-enzyme complexes with a dye specific for protein showed that only the carrier external surface was availabl e for protein binding. When confined in a packed bed reactor, the acti vity of the co-immobilized enzymes brought about a viscosity decrease of 70-90% in pectin and polygalacturonic acid solutions, respectively. Sixty per cent of the initial activity was retained from the immobili zed enzymes after the sixth utilization cycle on both the substrates u sed. The immobilized enzymes were also active against fresh apple juic e producing a 90% reduction in viscosity in the first five cycles of u tilization. (C) 1997 Elsevier Science Ltd.