Abstract
β-galactosidase from Aspergillus oryzae was strongly immobilized on magnetic particles functionalized with amino groups. By
simple incubation without any activating agents, electrostatic interactions between amino groups and enzymes allowed obtaining
a strong linkage. The immobilization efficiency was studied with the quantification of amino groups of the particles and of
immobilized β-galactosidase. Kinetic parameters, especially the maximal velocity Vmax and the affinity Km, were determined
with two substrates, o-NPG and lactose, and compared with free enzyme values in order to evaluate the influence of our
immobilization methodology on the kinetic behavior of the enzyme. Therefore, magnetic capacity of the functionalized particles
allows recovering and reusing the support. Results show efficient immobilization of β-galactosidase (58 μg/mg of support), able
to hydrolyze substrates during multiple cycles of use. Thus, magnetic particles functionalized with amino groups represent an
attractive support for simple and efficient β-galactosidase immobilization process.