Study on the behaviour of glucose oxidase immobilized on microfiltration polyamide membrane

Microfiltration membranes of polyamide-6 (PA-6) were preliminarily modified by hydrochloric acid (HCl) and subsequently activated by 1,2-diaminoethane (DAE). They were used as matrix for covalent immobilization of glucose oxidase (GOD) by using glutaraldehyde. Some characteristics of initial and modified membranes were studied: amino groups content, degree of hydrophilicity, water permeability, coefficient of permeability and average pore radius. The amount of bound protein and relative activity of GOD immobilized onto the modified membrane matrices were determined. The highest activity (81.4%) was measured for GOD immobilized onto membrane modified with 6 wt.% hydrochloric acid and 10 wt.% DAE. The properties of GOD immobilized onto modified PA-6 membranes were also determined: pH and temperature optimum, pH and thermal stabilities and storage period of enzyme activity and were compared to those of the native enzyme.