Abstract: The invention relates to a method for recovering a basic amino acid from the fermentation liquor of a micro-organism strain that produces the basic amino acid. The method comprises the following steps: a) isolation of the micro-organisms from the fermentation liquor and b) separation of the basic amino acid from the aqueous liquor that has been obtained in step a) by the successive charging of a single or multiple stage arrangement of a strongly acidic cation exchanger in the form of a salt with the liquor obtained in step a) and the elution of the basic amino acid. According to the invention, prior to the charging process in step b), the aqueous liquor has a pH value ranging between 4 and 7.5 and at least the first stage of the carbon exchanger arrangement is pre-treated with an aqueous acid in such a way that at the end of said pre-treatment, the pH value at the discharge of the pre-treated cation exchanger ranges between 4.5 and 7.

Abstract: The invention relates to a method for recovering a basic amino acid from the fermentation liquor of a micro-organism strain that produces the basic amino acid. The method comprises the following steps: a) isolation of the micro-organisms from the fermentation liquor and b) separation of the basic amino acid from the aqueous liquor that has been obtained in step a) by the successive charging of a single or multiple stage arrangement of a strongly acidic cation exchanger in the form of a salt with the liquor obtained in step a) and the elution of the basic amino acid. According to the invention, prior to the charging process in step b), the aqueous liquor has a pH value ranging between 4 and 7.5 and at least the first stage of the carbon exchanger arrangement is pre-treated with an aqueous acid in such a way that at the end of said pre-treatment, the pH value at the discharge of the pre-treated cation exchanger ranges between 4.5 and 7.