REVERSIBLE ADSORPTION OF ENDOPECTIN-LYASE TO TAILOR-MADE CORE-SHELL MICROSPHERES PREPARED BY DISPERSION POLYMERIZATION

The reversible adsorption behaviour of endopectin-lyase on tailor-made microspheres prepared by free-radical dispersion polymerization of st yrene using a polyacid, Eudragit, as the steric stabilizer is describe d, Four functional microsphere samples in the 2,0-7.7 mu m-diameter ra nge, differing in sire, dispersity, diameter distribution and Eudragit content, were employed, All the microsphere samples display a very si milar endopectin-lyase adsorption behaviour, which is strongly affecte d by the pH of the medium, Irrespective of the microsphere size and su rface Eudragit content, the endopectin-lyase adsorption yield decrease s with increasing pH and shows its highest value, corresponding to the highest affinity, at pH 4.7, The endopectin-lyase-adsorption-determin ing parameter is the Eudragit surface density. Complete and fast desor ption of the enzyme in the active form from the microsphere surface wa s also observed, In addition, the duration of the catalytic activity o f the enzyme-microsphere complex was longer than that of the free enzy me, These results show that the microsphere samples are effective chro matographic supports for pectolytic enzyme separation and purification and for the preparation of stable enzyme-microsphere complexes to be employed as biocatalysts in industrial processes.