Method for Producing an Acidic Substance Having a Carboxyl Group

Abstract

An acidic substance having a carboxyl group is produced by culturing in a medium a microorganism which has been modified to enhance expression of the ybjL gene, and collecting the acidic substance having a carboxyl group from the medium.

1 . A method for producing an acidic substance having a carboxyl group comprising culturing in a medium a microorganism, having an ability to produce the acidic substance having a carboxyl group, to produce and accumulate the acidic substance having a carboxyl group in the medium, and
 collecting the acidic substance having a carboxyl group from the medium,   wherein the acidic substance is succinic acid,   wherein the microorganism has been modified to enhance expression of an ybjL gene, and   wherein the ybjL gene encodes a protein selected from the group consisting of:   (A) a protein comprising the amino acid sequence of SEQ ID NO: 2; and   (B) a protein comprising a variant of the amino acid sequence of SEQ ID NO: 2, wherein one to 5 amino acid residues are substituted, deleted, inserted or added, and wherein, upon expression, said variant improves the ability of the microorganism to produce the acidic substance having a carboxyl group.   
     
     
         2 . The method according to  claim 1 , wherein said enhanced expression is obtained by a method selected from the group consisting of: A) increasing copy number of the ybjL gene, B) modifying an expression control sequence of the ybjL gene, and C) combinations thereof. 
     
     
         3 . The method according to  claim 1 , wherein the microorganism is a bacterium belonging to the family Enterobacteriaceae. 
     
     
         4 . The method according to  claim 3 , wherein the bacterium belongs to a genus selected from the group consisting of  Escherichia, Enterobacter, Raoultella, Pantoea , and  Klebsiella.    
     
     
         5 . The method according to  claim 1 , wherein the microorganism is a rumen bacterium. 
     
     
         6 . The method according to  claim 5 , wherein the microorganism is a bacterium belonging to the genus  Mannheimia.    
     
     
         7 . A method for producing an acidic substance having a carboxyl group comprising
 A) allowing a substance to act on an organic raw material in a reaction mixture containing carbonate ions, bicarbonate ions, or carbon dioxide gas, wherein said substance is selected from the group consisting of:   i) a microorganism having an ability to produce the acidic substance having a carboxyl group,   ii) a product obtained by processing the microorganism of i), and   iii) combinations thereof, and   B) collecting the acidic substance having a carboxyl group,   wherein the acidic substance is succinic acid,   wherein the microorganism has been modified to enhance expression of an ybjL gene, and   wherein the ybjL gene encodes a protein selected from the group consisting of:   (a) a protein comprising the amino acid sequence of SEQ ID NO: 2; and   (b) a protein comprising a variant of the amino acid sequence of SEQ ID NO: 2, wherein one to 5 amino acid residues are substituted, deleted, inserted or added, and wherein, upon expression, said variant improves the ability of the microorganism to produce the acidic substance having a carboxyl group.   
     
     
         8 . The method according to  claim 7 , wherein said enhanced expression is obtained by a method selected from the group consisting of: A) increasing copy number of the ybjL gene, B) modifying an expression control sequence of the ybjL gene, and C) combinations thereof. 
     
     
         9 . The method according to  claim 7 , wherein the microorganism is a bacterium belonging to the family Enterobacteriaceae. 
     
     
         10 . The method according to  claim 9 , wherein the bacterium belongs to a genus selected from the group consisting of  Escherichia, Enterobacter, Raoultella, Pantoea , and  Klebsiella.    
     
     
         11 . The method according to  claim 7 , wherein the microorganism is a rumen bacterium. 
     
     
         12 . The method according to  claim 11 , wherein the microorganism is a bacterium belonging to the genus  Mannheimia.    
     
     
         13 . A method for producing a polymer comprising succinic acid, comprising:
 A) producing succinic acid by the method according to  claim 1 , and   B) polymerizing the obtained succinic acid.   
     
     
         14 . A method for producing a polymer comprising succinic acid, comprising:
 A) producing succinic acid by the method according to  claim 7 , and   B) polymerizing the obtained succinic acid.