Characterization and optimization of immobilized polyphenol oxidase in low-water organic solvents

Polyphenol oxidase catalyses the aerobic regioselective oxidation of monophenols to o-di-phenols followed by dehydrogenation to o-quinones. This enzyme is inactivated during the reaction by a mechanism not well understood, although several authors have pointed to quinone polymers formed in aqueous media as the inactivation agent. Low water-content organic solvents have been regarded as potential reaction media because quinone polymerization is decreased. The immobilized polyphenol oxidase reaction was studied in almost anhydrous chloroform and the optimum pH (7.0) and temperature (30 o C) determined. The reaction was dependent on ionic strength and it was necessary to maintain this parameter as low as possible.