Method of producing L-serine by fermentation

Abstract

L-serine is produced by cultivating in a medium a coryneform bacterium having L-serine productivity in which an activity of at least one of phosphoserine phosphatase and phosphoserine transaminase is enhanced, preferably, further having introduced therein a gene coding for D-3-phosophoglycerate dehydrogenase in which feedback inhibition by L-serine is desensitizied, allowing L-serine to accumulate in the medium, and collecting the L-serine from the medium.

What is claimed is:  
     
         1 . A coryneform bacterium having L-serine productivity in which an activity of at least one of phosphoserine phosphatase and phosphoserine transaminase is enhanced.  
     
     
         2 . The coryneform bacterium as claimed in  claim 1 , wherein said bacterium is enhanced the activitise of both phosphoserine phosphatase and phosphoserine transaminase.  
     
     
         3 . The coryneform bacterium as claimed in  claim 1 , wherein said bacterium has L-serine productivity due to deficiency in L-serine decomposing activity.  
     
     
         4 . The coryneform bacterium as claimed in  claim 1  or  3 , wherein said bacterium has L-serine productivity due to its resistance to L-serine analogue(s).  
     
     
         5 . The coryneform bacterium as claimed in  claim 1 , wherein an activity of phosphoserine phosphatase or phosphoserine transaminase is enhanced by increasing a copy number of a gene coding for phosphoserine phosphatase or a gene coding for phosphoserine transaminase in said coryneform bacterium in its cell.  
     
     
         6 . The coryneform bacterium as claimed in any one of  claims 1  to  5 , wherein said bacterium has introduced therein a gene coding for D-3-phosophoglycerate dehydrogenase in which feedback inhibition by L-serine is desensitized.  
     
     
         7 . A method of producing L-serine, comprising the steps of cultivating the coryneform bacterium as claimed in any one of  claims 1  to  6  ndescribed above in a medium to accumulate L-serine in the medium and collecting the L-serine from the medium.