Effect of culture conditions on the production of D-galactose oxidase by Dactylium dendroides.

The effects on enzyme production of inoculum size and age, medium composition, and culture conditions were studied in shake flasks and in a pilot-plant fermentor. Using a medium consisting of glucose, yeast extract, and inorganic salts in deionized water, we found that the addition of Cu(++) was essential for the formation of active enzyme. Cultures grown in the absence of added copper produced an inactive enzyme protein which could be activated by 10(-3) M Cu(++). Thiamine fulfilled all requirements for exogenous vitamins for growth and enzyme production. Glucose concentrations higher than 1% markedly suppressed enzyme formation. The mycelium inactivated the enzyme on prolonged incubation of the culture. Mycelial autolysates and sonic extracts were found to contain a thermostable and slowly dialyzable galactose oxidase-inactivating factor. The experiments suggest that this factor operates as a chelating agent which forms complexes with the copper of the enzyme. Copper ions (10(-3) M) prevented enzyme inactivation and restored activity to samples previously inactivated by this factor.