Improved Stabilization of Genetically Modified Penicillin G Acylase in the Presence of Organic Cosolvents by Co‐ Immobilization of the Enzyme with Polyethyleneimine

Penicillin G acylase (PGA) is an enzyme that hardly interacts with polycationic polymers (e.g., polyethyleneimine, PEI) and thus the enzyme cannot be stabilized against the action of organic solvents by its co‐immobilization with the polymer in the same support, neither covalently attached to the support nor adsorbed on the already immobilized enzyme. However, a new mutant PGA bearing eight additional Glu residues homogenously distributed throughout the enzyme surface may interact with the polymer. The co‐immobilization of the enzyme and PEI on glyoxyl‐agarose allows one to fully take advantage of the stabilization produced by the multipoint covalent attachment and by the protective hydrophilic micro‐environment generated by the polycationic polymer, enabling a significant stabilization of the immobilized PGA in the presence of organic solvents.