Abstract: A bacterium which has an ability to produce an amino acid and in which a novel rhtB gene encodes a protein having an activity of making a bacterium having the protein L-homoserine-resistant is enhanced, is cultivated in a culture medium to produce and cause accumulation of the amino acid in the medium, and the amino acid is recovered from the medium.

Abstract: The present invention relates to a method for producing L-amino acids, such as L-tryptophan, L-phenylalanine, and L-tyrosine, using a bacterium belonging to the genus Escherichia, and wherein the L-amino acid productivity of said bacterium is enhanced by enhancing a PEP carboxykinase activity, which is coded by the pckA gene.

Abstract: A bacterium which has an ability to produce an amino acid and in which a novel rhtB gene encodes a protein having an activity of making a bacterium having the protein L-homoserine-resistant is enhanced, is cultivated in a culture medium to produce and cause accumulation of the amino acid in the medium, and the amino acid is recovered from the medium.

Abstract: The present invention describes a bacterium which has an ability to produce an amino acid and in which the rhtC gene encoding a protein having an enhanced activity of imparting L-threonine resistance to a bacterium expressing the protein. Preferably, the bacterium further includes an rhtB gene encoding for a protein having an enhanced activity of imparting to a bacterium L-homoserine resistance expressing the protein. The present invention also describes a method of cultivating the bacterium in a culture medium to produce and accumulate amino acids in the medium, and the amino acid is recovered from the medium.