METHOD OF CITRIC ACID PRODUCING Russian patent published in 1995 - IPC

FIELD: biotechnology. SUBSTANCE: method involves submerged fermentation of fungus Aspergillus niger on the media containing defective reed molasses. Method involves dilution of defective reed molasses with color index 2.7-4.3 conventional units, buffering 44.1-51.6 per 1 N sulfuric acid solution and colloidal property 12.1-13.4% with hot water at the ratio 1:1, successive treatment with potassium ferrocyanide and ammonium oxalate, addition of nitrogen and phosphorus sorces and complex salt (potassium-nickel (II) chloride dihydrate or potassium-copper (II)
chloride dihydrate, or potassium-magnesium chloride hexahydrate, or potassium-zinc chloride) at concentration 0.2-0.3 g/l followed by fermentation carrying out at the content of dissolved oxygen in the medium 80-85% of saturation. Output of citric acid is 12.3 kg/m³·ddy, molasses loss is decreased by 45.7%. EFFECT: increased yield of product, simplified process. 3 tbl