| 摘要 |
<p>A method by which a hydrochloride of a basic amino acid is isolated from a basic-amino-acid fermentation liquid containing sulfate ions. The method is almost equal in product yield and quality to conventional techniques and is easier than these. The method is for obtaining crystals of a hydrochloride of a basic amino acid from a basic-amino-acid fermentation liquid containing sulfate ions or from a sulfate-ion-containing liquid reaction mixture resulting from an enzymatic reaction catalyzed by living cells of a microorganism producing a basic amino acid. The method is characterized by (1) adding the chloride of a metal selected from the group consisting of calcium, potassium, magnesium, and barium to the basic-amino-acid fermentation liquid or liquid enzymatic-reaction mixture containing sulfate ions to precipitate the sulfate ions as crystals of the sulfate of the metal, (2) removing the crystals of the metal sulfate from the solution of the basic amino acid, (3) cooling the basic-amino-acid solution from which the metal sulfate crystals have been removed, while keeping the solution in the state of being not saturated with the metal sulfate, to thereby precipitate the basic amino acid as crystals of the hydrochloride thereof, and (4) isolating the basic amino acid crystals.</p> |
