Characterisation of adsorbed invertase by a continuous-flow method

Invertase was adsorbed on three different carriers. The enzyme-support complexes were characterized within a test reactor consisting in a continuous-flow filtering system. Enzyme residual activity was monitored together with the lass of low-energy bound enzyme. Immobilized enzyme was characterized by a good residual activity, as compared to free-solution conditions. For the experimental configuration adopted, mass transfer limitations could be neglected for all enzyme-support complexes considered. Adsorption-isotherms were measured, in terms of specific activity of irreversibly adsorbed enzyme versus free enzyme concentration in the supernatant. The experimental data were correlated satisfactorily by Langmuir-type equations for invertase immobilization on two different carriers. The stability of irreversibly adsorbed invertase towards thermal inactivation phenomena was analyzed. Irreversibly adsorbed enzyme displayed improved temperature stability, as compared to soluble enzyme, independently of the physico-chemical properties of the support.