Gluconic acid production by Aspergillus niger with oxygen supply by hydrogen peroxide

The production of gluconic acid was carried out with high catalase containing Aspergillus niger mutant. This osmofil strain enables to convert the concentrated solutions of D-glucose (300g/l) to D-gluconic acid without gasing using hydrogen peroxide as oxygen source. A controlled addition of hydrogen peroxide based on the pO₂ measurement was performed. The conversion of 300g/l glucose solution was achieved with 7 hours and triple conversion (with biomass recycling) within 27 hours with yield with regard to the substrate over 98%. Kinetics of inactivation of glucose oxidasecatalase complex as a whole was examined. Some general factors influencing the inactivation of glucose oxidase and catalase in mycelium are discussed.