| Three species of white-rot fungi, Phlebia radiata, Phanerochaete chrysosporium, and Trametes versicolor, were monitored for laccase and lignin peroxidase production in a defined medium. P. radiata was selected for fed-batch reactor experiments due to its early laccase production, which was determined to be growth-associated. A second peak in laccase activity was observed after several days of nutrient deprivation and was attributed to autolysis of the culture. The effect of protease activity on the accumulation of extracellular laccase activity differed during primary and secondary metabolism, as observed under various conditions of nitrogen and glucose availability. A mixed culture of P. radiata and P. chrysosporium was grown on ammonium lignosulfonate, a by-product of the pulp and paper industry, as sole source of carbon and nitrogen. Under these conditions, laccase production appeared to exceed laccase production by P. radiata in defined culture medium. |
