The behaviour of an urease loaded membrane, obtained by chemically grafting butyl methacrylate (BMA) on a nylon sheet, has been studied under non-isothermal conditions. Hexamethylenediamine (HMDA) and glutaraldehyde were also used as spacer and binding agent, respectively. Results have shown that the catalytic activity of themembrane under non-isothermal conditions is increasedwhen compared with the one found under comparable isothermal conditions. In addition, it has been found that the presence of temperature gradients decreases the apparent Km and increases the apparent Vmax with respect to the same values obtained under isothermal conditions. The percentage activity increases induced by the presence of a temperature gradient have been found to decrease with increasing average temperature and urea concentration. Aparameter has also been identified correlating the percentage increase of enzyme activity under non-isothermal conditions with the hydrophobicity of the catalytic membrane, this parameter being the ratio between thermo-osmotic and hydraulic permeability. Results have been discussed in terms of reduction of diffusion limitations for substrate and products movement towards or away from the catalytic site by the process of thermodialysis. The usefulness of using non-isothermal bioreactors in industrial biotechnological processes and, in particular, in waste water treatment has been confirmed.
Urease immobilization on chemically grafted nylon membranesPart 2. Non-isothermal characterization / H., El Sherif; DE MAIO, Anna; S., Di Martino; E., Zito; S., Rossi; P., Canciglia; F. S., Gaeta; D. G., Mita. - In: JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC. - ISSN 1381-1177. - ELETTRONICO. - 14:(2001), pp. 31-43. [10.1016/S1381-1177(00)00240-X]
Urease immobilization on chemically grafted nylon membranesPart 2. Non-isothermal characterization
DE MAIO, ANNA;
2001
Abstract
The behaviour of an urease loaded membrane, obtained by chemically grafting butyl methacrylate (BMA) on a nylon sheet, has been studied under non-isothermal conditions. Hexamethylenediamine (HMDA) and glutaraldehyde were also used as spacer and binding agent, respectively. Results have shown that the catalytic activity of themembrane under non-isothermal conditions is increasedwhen compared with the one found under comparable isothermal conditions. In addition, it has been found that the presence of temperature gradients decreases the apparent Km and increases the apparent Vmax with respect to the same values obtained under isothermal conditions. The percentage activity increases induced by the presence of a temperature gradient have been found to decrease with increasing average temperature and urea concentration. Aparameter has also been identified correlating the percentage increase of enzyme activity under non-isothermal conditions with the hydrophobicity of the catalytic membrane, this parameter being the ratio between thermo-osmotic and hydraulic permeability. Results have been discussed in terms of reduction of diffusion limitations for substrate and products movement towards or away from the catalytic site by the process of thermodialysis. The usefulness of using non-isothermal bioreactors in industrial biotechnological processes and, in particular, in waste water treatment has been confirmed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
