L-amino acid producing microorganism which has been modified to inactive the fimH gene, and a method for producing I-amino acid

#1. Field of the Invention

#The present invention relates to the fermentation microbiological industry, and specifically to a method for producing an L-amino acid using a bacterium of the Enterobacteriaceae family, wherein the bacterium has been modified so as to not produce type I fimbrial adhesin protein. L-amino acids are employed as components of pharmaceuticals, animal feed additives, seasonings, and various other nutritive mixtures.

#2. Brief Description of the Related Art

#FIG. 1 shows the structure of pMW118-attL-Tc-attR and pMW118-attL-Cm-attR.

#FIG. 2 shows the structure of pMW-intxis-ts.

#<1> The Bacterium of the Present Invention

#The bacterium of the present invention is a bacterium having the ability to produce an L-amino acid and which belongs to the Enterobacteriaceae family. The bacterium of the present invention has been modified so as to not produce type I fimbrial adhesin protein. The ability to produce L-amino acids may include production of any single L-amino acid, or production of multiple L-amino acids. Examples of produced L-amino acids of the present invention include L-lysine, L-glutamic acid, L-threonine, L-valine, L-leucine, L-isoleucine, L-serine, L-aspartic acid, L-asparagine, L-glutamine, L-arginine, L-cysteine (cystine), L-methionine, L-phenylalanine, L-tryptophan, L-tyrosine, L-glycine, L-alanine, L-proline, L-ornithine, L-citrulline, and L-homoserine. L-lysine, L-threonine, and L-glutamic acid are particularly desirable.

#The phrase “ability to produce an L-amino acid” refers to the ability of a bacterium of the Enterobacteriaceae family to produce and cause accumulation of an L-amino acid in the bacterial cells or into a medium to a degree which permits its recovery from the bacterial cells or the medium when the bacterium is cultured in the medium. The bacterium which has this ability may originally have had the ability to produce an L-amino acid, or may be a bacterium, such as those set forth below, that has been modified by a mutation method or recombinant DNA technique to impart the ability to produce an L-amino acid. The bacterium of the present invention may also be one that has had the ability to produce an L-amino acid imparted to it by a modification which results in prevention of production of type I fimbrial adhesin production.