Process for removing oxalic acid from acidic fermentation liquids of citric acid-forming microorganisms

摘要

In this process, oxalic acid is precipitated as sparingly soluble calcium oxalate and the calcium oxalate is separated off. In order to remove the oxalic acid from the fermentation liquids as completely as possible and in an operationally safe manner and nevertheless prevent coprecipitation of sparingly soluble salts of citric acid without complicated monitoring measures in a reliable manner and moreover to increase the yield of citric acid obtainable from the fermentation liquids, the precipitation is carried out by adding calcium sulphate to the fermentation liquid before or after separation of the microorganism cells.