Patent ID: 8372606

Claim:
A method for obtaining the crystals of a basic amino acid hydrochloride from a fermentation broth containing the basic amino acid or an enzyme reaction solution containing the basic amino acid, said enzyme reaction is catalyzed by viable microbial cells producing the basic amino acid, and wherein the broth or the solution contains sulfate ions, the method comprising: (1) adding a metal chloride selected from the group consisting of calcium chloride, potassium chloride, magnesium chloride, and barium chloride to the fermentation broth containing the basic amino acid and sulfate ions or the enzyme reaction solution containing the basic amino acid and sulfate ions at pH of 3 to 8.5 and temperature of 20 to 90° C., thereby precipitating the sulfate ions as metal sulfate crystals, wherein the fermentation broth or the enzyme reaction solution comprises sulfate ions at a concentration of an equivalent ratio of 50 to 150% relative to the basic amino acid, (2) removing said metal sulfate crystals from said fermentation broth or the enzyme reaction solution, (3) cooling the fermentation broth or the enzyme reaction solution from which the metal sulfate crystals have been removed while maintaining the concentration of the metal sulfate below its saturation concentration, (4) precipitating the basic amino acid in the form of hydrochloride crystals, (5) separating basic amino acid hydrochloride crystals, and (6) collecting the basic amino acid hydrochloride crystals.