New applications of glyoxyl-octyl agarose in lipases co-immobilization: Strategies to reuse the most stable lipase.

Lipase B from Candida antarctica (CALB), lipase from Rhizomucor miehei (RML) and phospholipase Lecitase Ultra (LEU) were immobilized via interfacial activation and their stabilities were compared. Immobilized CALB was much more stable than immobilized RML or LEU. That meant that, if they were coimmobilized, after the inactivation of the least stable lipases, CALB should be discarded even though it may maintain full activity. This could be solved by sequential coimmobilization on octyl-glyoxyl (OCGLX). First, CALB was immobilized on OCGLX getting some covalent bonds between most of the CALB molecules and the support. Then, after reduction of CALB immobilized on OCGLX, RML or LEU can be immobilized on the support via interfacial activation. These enzymes could be released from the support just by using detergents, without affecting CALB activity. After optimization of the lipase desorption conditions, the bi-combilipases CALB/RML and CALB/LEU or the triple-combilipase CALB/RML/LEU could be submitted to several cycles of immobilized biocatalyst inactivation, desorption and enzyme reloading keeping the activity of the immobilized CALB almost intact. This way, by using OCGLX and a stepwise immobilization protocol, discarding all coimmobilized lipases when one becomes inactivated is no longer required. Thus, the most stable ones can be reused in several cycles.