Bacterium producing L-glutamic acid and method for producing L-glutamic acid

Abstract

L-Glutamic acid is produced by culturing a coryneform bacterium having L-glutamic acid producing ability, in which trehalose synthesis ability is decreased or deleted by, for example, disrupting a gene coding for trehalose-6-phosphate synthase, a gene coding for maltooligosyltrehalose synthase, or both of these genes to produce and accumulate L-glutamic acid in the medium, and collecting the L-glutamic acid from the medium.

What is claimed is:  
     
         1 . A coryneform bacterium having L-glutamic acid producing ability, wherein trehalose synthesis ability is decreased or deleted in the bacterium.  
     
     
         2 . The coryneform bacteria according to  claim 1 , wherein the trehalose synthesis ability is decreased or deleted by introducing a mutation into a chromosomal gene coding for an enzyme in trehalose systhesis pathway or disrupting the gene.  
     
     
         3 . The coryneform bacteria according to  claim 2 , wherein the gene coding for the enzyme in trehalose synthesis pathway consists of a gene coding for trehalose-6-phosphate synthase, a gene coding for maltooligosyltrehalose synthase, or both of these genes.  
     
     
         4 . The coryneform bacteria according to  claim 3 , wherein the gene coding for trehalose-6-phosphate synthase codes for the amino acid sequence of SEQ ID NO: 30, and the gene coding for maltooligosyltrehalose synthase codes for the amino acid sequence of SEQ ID NO: 32.  
     
     
         5 . A method for producing L-glutamic acid comprising the steps of culturing a coryneform bacterium according to any one of claims  1 - 4  in a medium to produce and accumulate L-glutamic acid in the medium, and collecting the L-glutamic acid from the medium.  
     
     
         6 . A DNA coding for a protein defined in the following (A) or (B): 
 (A) a protein having the amino acid sequence of SEQ ID NO: 30,    (B) a protein having the amino acid sequence of SEQ ID NO: 30 including substitution, deletion, insertion or addition of one or several amino acid residues and having trehalose-6-phosphate synthase activity.    
     
     
         7 . A DNA according to  claim 6 , which is a DNA defined in the following (a) or (b): 
 (a) a DNA containing a nucleotide sequence comprising at least the residues of nucleotide numbers 484-1938 in the nucleotide sequence of SEQ ID NO: 29,    (b) a DNA hybridizable with a nucleotide sequence comprising at least the residues of nucleotide numbers 484-1938 in the nucleotide sequence of SEQ ID NO: 29 under a stringent condition, showing homology of 55% or more to the foregoing nucleotide sequence, and coding for a protein having trehalose-6-phosphate synthase activity.    
     
     
         8 . A DNA coding for a protein defined in the following (A) or (B): 
 (A) a protein having the amino acid sequence of SEQ ID NO: 32,    (B) a protein having the amino acid sequence of SEQ ID NO: 32 including substitution, deletion, insertion or addition of one or several amino acid residues and having maltooligosyltrehalose synthase activity.    
     
     
         9 . A DNA according to  claim 8 , which is a DNA defined in the following (a) or (b): 
 (a) a DNA containing a nucleotide sequence comprising at least the residues of nucleotide numbers 82-2514 in the nucleotide sequence of SEQ ID NO: 31,    (b) a DNA hybridizable with a nucleotide sequence comprising at least the residues of nucleotide numbers 82-2514 in the nucleotide sequence of SEQ ID NO: 31 under a stringent condition, showing homology of 60% or more to the foregoing nucleotide sequence, and coding for a protein having maltooligosyltrehalose synthase activity.