Study of the stabilization of pure lipases: comparison of two different lipase-microgel derivatives

Abstract

The immobilization/stabilization of pure and very labile lipases was studied. Two types of lipase-microgels derivatives, which may be used in aqueous and/or organic media were designed and optimized. The first type consisting in the covalent linkage of the protein to the surface of a previously formed microgel. The second type was obtained in a reverse micellar system of AOT. The lipase was microencapsulated into the acrylic microgels formed after a polymerization process carried out in the micellar droplets. In this case, a crosslinking agent was simultaneously used to enhance the protein rigidity. Due to the distinct lipase localization the two microgel derivatives differ in their activities and stabilities: the microgel with the lipase at its surface had a similar activity and stability as the native lipase, while an important reduction of the conformational mobility of the protein was found when the lipase was microencapsulated, and it gave rise to a high stabilization factor. Thus, a new immobilization method which stabilizes by 352 times at 45°C the pure isolipase B from Candida cylindracea is described. These results were also better than those of the crude lipase stabilization by multipoint attachment to agarose gels.