The production of lignin peroxidase by Streptomyces viridosporus T7A was studied in shake flasks and under aerobic conditions in a 7.5-L batch fermentor. Lignin peroxidase synthesis was found to be strongly affected by catabolite repression. Lignin peroxidase was a non-growth-associated, secondary metabolite. The maximum lignin peroxidase activity was 0.064 U/mL at 36 h. In order to maximize lignin peroxidase activity, optimal conditions were determined. The optimal incubation temperature, pH, and substrate (2,4-dichlorophenol) concentration for the enzyme assays were 45 degrees C, 6, and 3 mM, respectively. Stability of lignin peroxidase was determined at 37, 45, and 60 degrees C, and over the pH range 4-9.

The production of peroxidases by Streptomyces viridosporus T7A and recombinant Streptomyces lividans TK64.1 was characterized in stirred tank fermentors. The rate of peroxidase production was strongly growth associated with plasmid‐coded S. lividans, in contrast to chromosome‐coded S. viridosporus, where peroxidase production was proportional to cell mass rather than cell growth rate. A modified form of the logistic equation gave a good fit to the experimenal data for cell growth and peroxidase formation.