Method for producing nucleotide by fermentation

Abstract

Nucleoside 5'-phosphate ester is produced by culturing a bacterium belonging to the genus Escherichia having an ability to produce nucleoside 5'-phosphate ester, in which ushA gene and aphA gene do not function normally, in a medium to produce and accumulate nucleoside 5'-phosphate ester in the medium, and collecting the nucleoside 5'-phosphate ester from the medium.

1 - 8 . (canceled)  
     
     
         9 . A method for producing nucleoside 5′-phosphate ester, comprising the steps of culturing a bacterium belonging to  Escherichia coli  having an ability to produce nucleoside 5′-phosphate ester, in which expression of ushA gene and aphA gene is decreased as compared to a wild type strain by mutating or disrupting the ushA gene and the alpha gene, in a medium containing glucose or sucrose to produce and accumulate nucleoside 5′-phosphate ester in a medium by direct fermentation, and collecting the nucleoside 5′-phosphate ester is selected from the group consisting of inosine 5′-phosphate ester and guanosine 5′-phosphate ester.  
     
     
         10 . The method according to  claim 9 , wherein the bacterium is further transformed with the mutant purF gene of  Escherichia coli  coding for PRPP amidotransferase in which the lysine residue at position 326 is replaced with a glutamine residue.  
     
     
         11 . The method according to  claim 10 , wherein the bacterium is further transformed with a guaBA operon of  Escherichia coli.    
     
     
         12 . The method according to  claim 9 , wherein the nucleoside 5′-phosphate ester is inosine 5′-phosphate ester.  
     
     
         13 . The method according to  claim 9 , wherein the nucleoside 5′-phosphate ester is guanosine 5′-phosphate ester.