Microorganism producing o-phosphoserine and method of producing l-cysteine or derivatives thereof from o-phosphoserine using the same

Abstract

The present invention provides methods for the production of cysteine or derivates thereof by culturing a microorganism having reduced activity of endogenous phosphoserine phosphatase. The O-phosphoserine produced by such an organism can then be reacted with a sulfide in the presence of a sulfydrylase or a microorganism expressing a sulfhydrylase to produce cysteine or a derivative thereof. Microorganisms having the properties noted above are also provided herein.

1 . A method for producing cysteine or a derivative thereof, comprising:
 1) culturing a recombinant microorganism in which the activity of endogeneous phosphoserine phosphatase (SerB) is reduced, to produce O-phosphoserine (OPS); and   2) reacting the OPS of step 1) with a sulfide in presence of O-phosphoserine sulfhydrylase (OPSS) or a microorganism expressing OPSS, to produce cysteine or a derivative thereof.   
     
     
         2 . The method of  claim 1 , wherein the phosphoserine phosphatase has an amino acid sequence of SEQ ID NO: 1 or 2. 
     
     
         3 . The method of  claim 1 , wherein the recombinant microorganism in which the activity of endogenous SerB is disrupted is cultured in a medium containing glycine or serine. 
     
     
         4 . The method of  claim 3 , wherein the medium contains glycine in an amount of from 0.1 to 10 g/L. 
     
     
         5 . The method of  claim 3 , wherein the medium contains serine in an amount of from 0.1 to 5 g/L. 
     
     
         6 . The method of  claim 1 , wherein the recombinant microorganism is  Escherichia  sp. or Coryneform bacteria. 
     
     
         7 . The method of  claim 1 , wherein the sulfide of step 2) is selected from the group consisting of Na 2 S, NaSH, (NH 4 ) 2 S, H 2 S, Na 2 S 2 O 3  and a combination thereof. 
     
     
         8 . The method of  claim 1 , wherein the OPSS of step 2) is from at least one species selected from the group consisting of  Aeropyrum pernix, Mycobacterium tuberculosis, Mycobacterium smegmatis  and  Trichomonas vaginalis.    
     
     
         9 . The method of  claim 8 , wherein the OPSS is a further modified to increase a conversion rate of step 2). 
     
     
         10 . The method of  claim 1 , wherein the conversion of step 2) is carried out in presence of a cofactor selected from 0.001 to 2 mM PLP (pyridoxal-5-phosphate), 0.001 to 100 mM DTT (dithiothreitol), and a combination thereof. 
     
     
         11 . The method of  claim 1 , further comprising isolating and purifying the cysteine or its derivatives.