Abstract
Different lipases (lipase B from
Candida Antarctica, CAL-B, lipase from
Thermomyces lanuginose, TLL and lipase from
Bacillus thermocatenulatus, BTL) and a phospholipase (Lecitase
® Ultra) were immobilized by interfacial activation on four different hydrophobic supports (hexyl- and butyl-toyopearl and butyl- and octyl-agarose) and their properties were compared. The results suggested that selection of different supports yielded very different results in terms of recovered activity (ranging from a sevenfold hyperactivation to almost fully inactive biocatalysts), stability, specificity and adsorption strength. Even more interestingly, the enantioselectivity of the enzymes in the hydrolysis of (±)-2-
O-butyryl-2-phenylacetic acid was strongly dependent on the support utilized. For example, BTL immobilized on octyl-agarose was fully enantiospecific towards the hydrolysis of (
S)-2-
O-butyryl-2-phenylacetic acid (
E
>
100), whereas when immobilized on hexyl-toyopearl, the enantiomeric value of the immobilized lipase was only
E
=
8. However, there is not an optimal support; it depends on the lipase and on the studied parameter. In the asymmetric hydrolysis of phenylglutaric acid diethyl diester, BTL immobilized on hexyl-toyopearl was the most enantioselective catalyst with ee
>
99% (A factor >100) in the production of
S-monoester product, whereas the enzyme immobilized on butyl-toyopearl only exhibited an A factor of 3.
Finally, butyl-agarose was chosen as the most specific support on the lipase adsorption – compared to other proteins – at low ionic strength yielding the best purification of BTL from crude preparations.