Adsorption of Candida rugosa lipase onto alumina: effect of surface charge

Abstract

The impact of the surface charge of alumina supports on the adsorption of Candida rugosa lipase was investigated in terms of the zeta potentials of the adsorption partners. The lipase adhered onto alumina with similar efficiency under both repulsive and attractive electrostatic conditions, shifting the zeta potential of the support towards that of the enzyme. The behavior was explained by a heterogeneous distribution of the surface charge of the lipase molecule. Special emphasis in this study was placed on the effect of immobilization on the enzyme kinetics and principal reasons for enzyme immobilization: improvement in stability and potential for reuse. The enzyme affinity was not altered by its adsorption onto alumina, while the Vmax value of the lipase decreased. The thermostability of the adsorbed lipase was improved. A significant potential for reuse was found.