Physical-chemical properties of the support immobead 150 before and after the immobilization process of lipase

Abstract

We carried out the physico-chemical characterization of Immobead 150, a hydrophobic support for the immobilization of lipases. Thermomyces lanuginosus lipase (TLL) was immobilized on Immobead 150 by multipoint covalent attachment (ImmTLL) and the morphological, textural, structural, thermal, and physico-chemical properties of the support, before and after enzyme immobilization, were investigated. Immobead 150 presents approximately 1,000 μmol of epoxy groups per gram of support, a high hydrophobicity, and good thermal stability. The spherical particles of Immobead 150 present average diameters of 155 μm, specific surface areas of 137 m2 g-1 and pore volumes of 0.37 cm3 g-1, showing pores in the region of the micro and meso sizes. The immobilization process of TLL (150 mg g-1) caused a decrease of the specific area and pore volumes, to 63 m2 g-1 and 0.25 cm3 g-1, respectively, as a result of coating of the support surface by the enzyme molecule. However, the immobilization process did not affect the morphology of the support. The obtained biocatalyst was effective for the syntheses of fatty acid ethyl esters (biodiesel), and of aroma esters, showing yields of 68 and 70%, respectively, similar to commercial preparations used as controls.