Optimization of catalase biosynthesis in submerged cultures of Aspergillus niger mutant.

The effect of some medium components, viscous substances and metabolic inhibitors, on catalase production by mutant Aspergillus niger has been studied in shake culture. Altering the composition of the basal medium, particularly substituting NaNO3 for KNO3, and peptone for yeast extract brought an increase in extra- and intracellular catalase activity by 1.5- and 3-fold, respectively. The addition of 2.0-6.0 mg sodium alginate or pectin/ml as viscous additive to the medium, containing glucose as carbon source, increased the medium viscosity and catalase production in shake culture by about 2.8- to 3.0-fold. The highest yield of extracellular catalase activity of A. niger was obtained in the presence of sodium orthovanadate and Triton X-100, which improved the activity of this enzyme by about 1.5-2.2-fold. A significant increase in intracellular catalase activity was observed in the presence of hematin, Tween 80 and sodium orthovanadate (1.7-, 1.6- and 1.4-fold respectively). The time course of growth and enzyme production by A. niger in the optimized medium is also reported.