CHARACTERIZATION OF THE ACTIVITY OF BETA-GALACTOSIDASE IMMOBILIZED ONTEFLON MEMBRANES PREACTIVATED WITH DIFFERENT MONOMERS BY GAMMA-IRRADIATION

The activity of P-galactosidase, immobilized by grafting technique on Teflon membranes preactivated with four different monomers, has been c haracterized from the biochemical and biophysical points of view. The monomers used were acrylic acid or acrylamide, or methacrylic acid and 2-hydroxyethyl methacrylate. When 2-hydroxyethyl methacrylate was use d in the second grafting, the first three monomers have been used in t he first modification step. The behavior of the free and immobilized e nzyme has been analyzed as a function of temperature and pH. For each catalytic membrane, we have found general equations relating the absol ute enzyme activity to pH and temperature. From these expressions, the experimental conditions giving the best yield of each catalytic membr ane have been calculated. The kinetic parameters for the four membrane s have also been determined. The advantages of using these membranes i n nonisothermal bioreactors are also indicated. (C) 1998 John Wiley & Sons, Inc.