HEAT-DENATURATION KINETICS OF LIGNIN PEROXIDASES FROM PHANEROCHAETE-CHRYSOSPORIUM

Many practical applications have been proposed for the lignin peroxidases from Phanerochaete chrysosporium. To design and develop these technologies, more information regarding the stability of these enzymes is required. Heat-denaturation studies were conducted on crude and partially purified lignin peroxidases obtained from P. chrysosporium under nitrogen-limiting and nitrogen-sufficient conditions. At temperatures of 37°C, or below, no significant loss of activity was observed over a 5-d period. At temperatures between 50 and 60°C, lignin peroxidase activity rapidly decreased. The heat-denaturation kinetics under these conditions was not first order. A four-parameter model that describes the heat-denaturation kinetics of crude and partially purified lignin peroxidases was developed. Based on the successful application of this model, it is suggested that P. chrysosporium produces lignin peroxidases that can be separated into at least two groups with similar decay constants within a group and different decay constants between groups. © 1990.