Influence of the non-isothermal conditions on the activity of enzymes immobilized on nylon grafted membranes

beta -Galactosidase was immobilized on a nylon membrane chemically grafted with butylmethacrylate. Hexamethylenediamine was used as spacer;and glutaraldehyde as coupling agent. The catalytic behaviour of the membrane was studied under isothermal and non-isothermal conditions. It was found that in the presence of temperature gradients, the catalytic membrane exhibited higher activity and greater affinity for the substrate. The increases of the enzyme reaction rate was found to be proportional to the intensity of the applied temperature gradient. Percentage increases of the activity were also found to decrease with the increase of the average temperature and concentration. All the results are phenomenologically discussed in terms of substrate traffic across the catalytic membrane induced by the processes of diffusion or thermodialysis under isothermal and non-isothermal conditions, respectively. (C) 2000 Published by Elsevier Science B.V.