Impact of structural features of halloysite nanotubes on adsorption and catalytic properties of β-galactosidase

β-Galactosidase from the fungus Aspergillus oryzae was immobilized on halloysite nanotubes of various origins and internal diameters. Enzyme adsorption was found to reach 1.3 mg m⁻² for nanotubes with an internal diameter of 50 nm, but it was half that for nanotubes with a smaller diameter (12.5 nm) owing to the poor accessibility of the nanotube’s internal surface for the adsorption of large protein molecules (M_r ~110 kDa), regardless of the support acidity. β-Galactosidase layers immobilized on the halloysite surface retain 10–27% of activity and are 3–6 times more stable than the native enzyme, with the best results associated with protein molecules encapsulated inside the pores.