Tyrosinase immobilized on a hydrophobic membrane

Polyvinylidene fluoride (PVDF) membrane surfaces were ad hoc functionalized chemically to make them suitable for enzymatic immobilization. The process was performed by grafting the membrane surface with 1,4-diaminobutane and subsequently by activating it with glutarhaldehyde. The chemico-physical properties of the original PVDF membrane and of the modified membranes were studied by infrared spectroscopy, scanning electron microscopy, and static contact angle measurements. The activated membranes were used as a support for covalent immobilization of tyrosinase. The activity of free and immobilized enzyme was studied and compared. The experimental data showing the specific activity of the immobilized enzyme are similar to the value obtained with the free one. This means that the immobilization procedure did not alter the catalytic properties of the tyrosinase. In addition, the surface modification of the PVDF made it a promising material to use in enzyme or biomolecule immobilization processes.