Lactose hydrolysis by β-galactosidase immobilized on two nylonmembranes, differently grafted, has been studied in a bioreactor operating under isothermal and non-isothermalconditions. One membrane (M1) was obtained by chemical grafting of methylmethacrylate (MAA); the other one (M2) by a double chemical grafting: styrene (Sty) and MAA. Hexamethylenediamine was used as a spacer between the graftedmembranes and the enzyme. Both membranes have been physically characterized studying their permeabilities in presence of pressure or temperature gradients. Under non-isothermalconditions, the increase in activity of membrane M2 was higher than that of membrane M1. The α and β coefficients, giving the percentage of activity increase when a temperature difference of 1°C is applied across the catalytic membranes, have been calculated. Results have been discussed with reference to the greater hydrophobicity of membrane M2 with respect to membrane M1, the hydrophobicity being a prerequisite for the occurrence of the process of thermodialysis.
Modulation of immobilized enzyme activity by altering the hydrophobicity of nylon-grafted membranes. Part 2: Non-isothermal conditions / M. M., E.M., DE MAIO, A., S., D.M., U., B., S., R., B. A., M., N., P., P., C., M., P., F. S., G., D. G., M.. - In: JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC. - ISSN 1381-1177. - ELETTRONICO. - 9:(2000), pp. 231-244. [10.1016/S1381-1177(99)00099-5]
Modulation of immobilized enzyme activity by altering the hydrophobicity of nylon-grafted membranes. Part 2: Non-isothermal conditions
DE MAIO, ANNA;
2000
Abstract
Lactose hydrolysis by β-galactosidase immobilized on two nylonmembranes, differently grafted, has been studied in a bioreactor operating under isothermal and non-isothermalconditions. One membrane (M1) was obtained by chemical grafting of methylmethacrylate (MAA); the other one (M2) by a double chemical grafting: styrene (Sty) and MAA. Hexamethylenediamine was used as a spacer between the graftedmembranes and the enzyme. Both membranes have been physically characterized studying their permeabilities in presence of pressure or temperature gradients. Under non-isothermalconditions, the increase in activity of membrane M2 was higher than that of membrane M1. The α and β coefficients, giving the percentage of activity increase when a temperature difference of 1°C is applied across the catalytic membranes, have been calculated. Results have been discussed with reference to the greater hydrophobicity of membrane M2 with respect to membrane M1, the hydrophobicity being a prerequisite for the occurrence of the process of thermodialysis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
