Patent ID: 8859243

Claim:
A method for producing an L-amino acid by fermentation comprising A) culturing a microorganism which is able to produce the L-amino acid in a liquid medium so that the L-amino acid precipitates into the medium, wherein the medium contains 10 mg/L or more of a polymer selected from the group consisting of a water-soluble cellulose derivative, a water-soluble polyvinyl compound, a polar organic solvent-soluble polyvinyl compound, a water-soluble starch derivative, an alginic acid salt, and a polyacrylic acid salt, wherein said water-soluble cellulose derivative is selected from the group consisting of carboxymethylcellulose, methylcellulose, sodium carboxymethylcellulose, hydroxypropylcellulose, and hydroxypropylcellulose phthalate; and wherein said water-soluble starch derivative is selected from the group consisting of hydroxypropyl starch and gelatin; and B) collecting the L-amino acid from the medium or the microorganism, wherein said L-amino acid is selected from the group consisting of L-tryptophan, L-phenylalanine, L-tyrosine, L-isoleucine, L-leucine and L-valine, and wherein the microorganism can accumulate the amino acid in an amount of 10.6 g/L or more in the case of L-tryptophan fermentation, 27.4 g/L or more in the case of L-phenylalanine fermentation, 0.38 g/L or more in the case of L-tyrosine fermentation, 41.2 g/L or more in the case of L-isoleucine fermentation, 23.8 g/L or more in the case of L-leucine fermentation, or 57.5 g/L or more in the case of L-valine fermentation.