A covalent immobilization method based on glutaraldehyde and amino-functionalized SBA-15 supports
has been successfully applied to covalently and stably immobilize laccase from Trametes versicolor. The
resultant biocatalysts displayed high incorporation yields of enzyme and led to excellent biodegradation
rates of selected HPAs models, i.e. naphthalene, phenanthrene and anthracene, in water. The nature of the
hydrocarbon chain accompanying the amino group has been shown as determinant for the immobilization
as well as for the activity and reusability of the materials. Thus, alkyl moieties displayed higher
enzyme loadings than phenyl moieties, being more adequate the larger n-butyl tethering residue likely
due to its higher mobility. Using the aminobutyl-based laccase-SBA-15, 82%, 73%, and 55% conversion
of naphthalene, phenanthrene and anthracene, respectively, were achieved after 48 h, very close to the
values obtained with free laccase under the same reaction conditions. On the other hand,
aminopropyl-based laccase-SBA-15 biocatalysts displayed the best reusability properties, retaining
higher activity after four repeated uses than the corresponding aminobutyl-based materials.