RECOVERING METHOD FOR AMINO ACID FROM FERMENTATION LIQUOR

PURPOSE:To recover an amino acid in high yield without diluting a fermentation liquor, by adding a specific organic solvent to an amino acid fermentation liquor containing microbial cells, stirring the resultant mixture, subjecting the mixture solution to centrifugal settling and separating the water layer containing dissolved amino acid. CONSTITUTION:An organic solvent capable of forming two layers with water without dissolving an amino acid, e.g. toluene, n-butanol or methyl isobutyl ketone, is added to an amino acid fermentation liquor containing microbial cells and the resultant mixture solution is stirred. The obtained whole microbial cell-organic solvent-water emulsion or a microbial emulsion layer prepared by allowing the emulsion to stand and separating from the water layer is subjected to centrifugal settling (60-250G centrifugal effect for 5-10min centrifugal settling time) to separate the water layer containing no microbial cell dissolving the amino acid from other layers, separate and recover the amino acid from the above-mentioned water layer. Water is then added to a microbial cell emulsion layer separated from the water layer by the centrifugal settling and the resultant mixture is further subjected to centrifugal settling. Thereby the recovery of the amino acid can be improved by using a small amount of washing water.