A novel immobilized chloroperoxidase biocatalyst with improved stability for the oxidation of amino alcohols to amino aldehydes

Abstract

► Chloroperoxidase from Caldariomyces fumago was immobilized on aminated support. ► The immobilized preparation showed within 51 and 77% of the initial CPO activity. ► Covalently attached CPO was within 311 and 528-fold more stable than soluble CPO. ► Immobilized CPO increased Cbz-glycinal production compared to soluble enzyme. Chloroperoxidase from Caldariomyces fumago (CPO, EC 1.11.1.10) is one of the most promising of the heme peroxidase enzymes for synthetic applications. Since the synthetic use of CPO suffers severely from its rapid deactivation in the presence of peroxides, the immobilization of this enzyme was studied as a possibility for stability improvement. Three methods of immobilization were considered using monoaminoethyl-N-aminoethyl (MANA) agarose gels: ionic adsorption, covalent attachment via carbodiimide coupled activation and covalent attachment of oxidized CPO. The most successful results led to almost complete immobilization with retained activities of around 51% for the two methods of covalent attachment and 77% for the ionic adsorption of CPO on MANA. Besides, all of the immobilized enzyme systems showed drastically improved stability toward presence of peroxide; CPO immobilized on MANA through carbodiimide coupled method resulted to be the most stable one with an increase in apparent half-life time of more than 500-fold that of the soluble enzyme. CPO immobilized by this method was compared to the soluble enzyme as catalyst for Cbz-ethanolamine oxidation to Cbz-glycinal using tert -butyl hydroperoxide (t-BuOOH) as an oxidant. Despite the lower reaction rate, the reaction catalyzed by immobilized CPO reached higher Cbz-glycinal yield with almost three-fold lower activity loss.