Characterization and application of a sterol esterase immobilized on polyacrylate epoxy-activated carriers (Dilbeads™)

The sterol esterase from the ascomycete Ophiostoma piceae was immobilized on novel polyacrylate-based epoxy-activated carriers (Dilbeads™). Six supports with particle sizes between 120 and 165 μm were prepared varying the composition of monomers, cross-linkers and porogens. Their surface areas and porosities were determined by N2 adsorption and mercury intrusion porosimetry. The pore volumes ranged from 0.63 to 1.32 cm3/g, but only Dilbeads™ RS and NK had narrow pore size distributions (with maxima at 33.5 and 67.0 nm, respectively). The distribution of the enzyme in the support was studied by fluorescence confocal microscopy. The immobilized esterase on Dilbeads™ TA showed a significant pH and thermal stability and was assayed in the continuous hydrolysis of cholesteryl esters –present in the pulp industry process waters.