Improved operational stability of peroxidases by coimmobilization with glucose oxidase

The operational stability of peroxidases was considerably enhanced by gener ating hydrogen peroxide in situ from glucose and oxygen. For example, the t otal turnover number of microperoxidase-11 in the oxidation of thioanisole was increased sevenfold compared with that obtained with continuous additio n of H2O2. Coimmobilization of peroxidases with glucose oxidase into polyurethane foam s afforded heterogeneous biocatalysts in which the hydrogen peroxide is for med inside the polymeric matrix from glucose and oxygen. The total turnover number of chloroperoxidase in the oxidation of thioanisole and cis-2-hepte ne was increased to new maxima of 250 . 10(3) and 10 . 10(3), respectively, upon coimmobilization with glucose oxidase. Soybean peroxidase, which norm ally shows only classical peroxidase activity, was transformed into an oxyg en-transfer catalyst when coimmobilized with glucose oxidase. The combinati on catalyst mediated the enantioselective oxidation of thioanisole [50% ee (S)] with 210 catalyst turnovers. (C) 2000 John Wiley & Sons, Inc.