Production of citric acid by submerged fermentation

The process of producing citric acid by submerged aerobic fermentation which comprises

• inoculating a carbohydrate-containing medium with a mycelial pellet of a citric acid-producing microorganism, said pellet having been produced by having treated the spores of a citric acid-producing microorganism in a carbohydrate-containing medium free of unbound cyanide ions with ferro- or ferri-cyanide ions during the physiologically intensive development period which takes place during the transition period ranging from spore-swelling stage to the spore-germination stage, and characterized by its substantial absence of an adaptation lag in the fermentation as evidenced by its pH curve and
• producing citric acid at a substantially constant rate from the time of the inoculation of the fermentation medium with the pellet throughout, and to the end of the fermentation.

The method of preparing mycelial pellets of a citric acid-producing microorganism for the manufacture of citric acid in a carbohydrate-containing growth medium which comprises treating spores of a citric acid-producing microorganism in the carbohydrate-containing growth medium free of unbound cyanide ions by adding ferro- or ferri-cyanide ions in an amount of 0.25 to 1.5 g per liter of medium during the physiologically intensive development period which takes place during the transition period ranging from the spore-swelling stage to the spore-germination stage, and forming mycelial pellets therefrom.