Industrial Production of Citric Acid Application of Citric Acid: (text,p.524) Acidulant in food, confectionary, and beverage (75%) Pharmaceutical (10%), e.g. soluble aspirin preparation - industrial (15%): complexes with metals such as iron and copper to be stabilizer of oil and fats.

Citric Acid Production by Aerobic Bioprocesses Wikipedia

Industrial Production of Citric Acid Microorganism: Aspergillus niger (mainly), Candida yeast (from carbohydrates or n-alkanes) Citric acid production is mixed growth associated, mainly take place under nitrogen and phosphate limitation after growth has ceased. Medium requirements for high production - Carbon source: molasses or sugar solution. - Na-ferrocyanide is added to reduce Iron (1.3 ppm) and manganese (<0.1ppm). - High dissolved oxygen concentration - High sugar concentration - pH<2 - 30 oC.

Industrial Production of Citric Acid Bioreactor: batch or fed-batch (100m3) 5-25X106 A. niger spores/L may be introduced to the fermentor. Aeration is provided to the fermenter by air sparging (0.1-0.4 vvm) Temperature is controlled by cooling coil. Agitation: 50-100rpm to avoid shear damage on molds. Fed-batch is used to reduce substrate inhibition and prolong the production phase one or two days after growth cessation. Volumetric yield: 130 kg/m3 Limitation of nitrogen and phosphate provoke an overflow in metabolism that results in an overproduction of citric acid.

Industrial Production of Citric Acid Separation: - The biomass is separated by filtration - The liquid is transferred to recovery process: - Separation of citric acid from the liquid: precipitation calcium hydroxide is added to obtain calcium citrate tetrahydrate → wash the precipitate→ dissolve it with dilute sulfuric acid, yield citric acid and calcium sulfate precipitate → bleach and crystallization → anhydrous or monohydrate citric acid.