Gluconic
Acid
Fermentations -
Gluconic acid used in pharmaceutical industries is produced by the fermentation of glucose either by strains of Aspergillus niger, Penicillium sp., or selected bacteria. In the commercial process, a nutrient solution containing 24-38 per cent glucose, corn steep liquor, a nitrogen source and salts, with pH 4.5 is used to culture a selected strain of fungus in shallow pans or in submerged culture conditions to convert glucose into gluconic acid. The pH of the medium is controlled by the addition of a strong solution of sodium hydroxide. Fermentation is carried out at 33 or 34°C.
