Methods for producing L-amino acids

Abstract

A bacterium belonging to the genus Escherichia having an ability to produce an L-amino acid is cultured in a medium containing fructose as a main carbon source, preferably a medium containing a carbon source composed of 30 weight % or more of fructose and 70 weight % or less of glucose, to produce and accumulate the L-amino acid in the medium, and the L-amino acid is collected from the medium.

What is claimed is:  
     
         1 . A method for producing an L-amino acid, which comprises culturing a bacterium belonging to the genus Escherichia having an ability to produce the L-amino acid in a medium containing fructose as a main carbon source to produce and accumulate the L-amino acid in the medium and collecting the L-amino acid from the medium.  
     
     
         2 . The method for producing an L-amino acid according to  claim 1 , wherein the medium contains 30 weight % or more of fructose with respect to the total amount of carbon source.  
     
     
         3 . The method for producing an L-amino acid according to  claim 1 , wherein the medium contains 30 weight % or more but 95 weight % or less of fructose with respect to the total amount of carbon source.  
     
     
         4 . The method for producing an L-amino acid according to  claim 1 , wherein the medium contains 30 weight % or more of fructose and 70 weight % or less of glucose with respect to the total amount of carbon source.  
     
     
         5 . The method for producing an L-amino acid according to any one of  claims 1  to  4 , wherein the bacterium belonging to the genus Escherichia is  Escherichia coli.    
     
     
         6 . The method for producing an L-amino acid according to any one of  claims 1  to  5 , wherein the L-amino acid is L-tryptophan.