Enterobacteriaceae fermentation strains

Abstract

Methods are provided for preparing improved fermentation strains of the family Enterobacteriaceae which comprise the steps of eliminating the cryptic plasmid from the progenitor strain thereby creating the improved strain. Methods for reducing the mobilization properties of resident plasmids in an Enterobacteriaceae strain containing a cryptic plasmid are also provided. The present invention provides the nucleic acid sequence of pS, a cryptic plasmid found in Pantoea which can be used to identify the cryptic plasmid in strains of Enterobacteriaceae.

1 - 19 . (canceled)  
     
     
         20 . An isolated amino acid sequence having the sequence as shown in SEQ ID NO: 3.  
     
     
         21 . An improved  Pantoea  strain derived from a progenitor strain having a native cryptic plasmid, wherein the native cryptic plasmid comprises a nucleic acid sequence which encodes an amino acid sequence having at least 95% sequence identity with SEQ ID NO: 3 and said cryptic plasmid having been deleted from the progenitor strain by recombinant or chemical means.  
     
     
         22 . The improved  Pantoea  strain of  claim 21 , wherein the progenitor strain is a  P. citrea  strain.  
     
     
         23 . The improved  Pantoea  strain of  claim 22 , wherein the  P. citrea  strain has ATCC accession number 31940.  
     
     
         24 . The improved  Pantoea  strain of  claim 21 , wherein the amino acid sequence has the sequence of SEQ ID NO: 3.  
     
     
         25 . The improved  Pantoea  strain of  claim 21 , wherein the cryptic plasmid has been deleted by chemical means.  
     
     
         26 . The improved  Pantoea  strain of  claim 21 , wherein the cryptic plasmid has been deleted by recombinant means.  
     
     
         27 . The improved  Pantoea  strain of  claim 21 , wherein the improved  Pantoea  strain is able to grow at a higher temperature than the progenitor strain.  
     
     
         28 . The improved  Pantoea  strain of  claim 21 , wherein the progenitor strain is capable of producing 2,5-diketo-D-gluconate from a carbon source.  
     
     
         29 . The improved  Pantoea  strain of  claim 21 , wherein the progenitor strain is a recombinant strain that comprises a heterologous nucleic acid sequence encoding a 2,5-diketo-D-gluconate reductase and is capable of converting 2,5-diketo-D-gluconate to 2-keto-L-gluconic acid.  
     
     
         30 . An improved  Pantoea citrea  strain derived from a progenitor strain having a native cryptic plasmid, wherein the native cryptic plasmid comprises a nucleic acid sequence which encodes an amino acid sequence having at least 95% sequence identity with SEQ ID NO: 3 and said cryptic plasmid having been deleted from the progenitor strain by recombinant or chemical means, wherein the improved  P. citrea  strain has an increased growth rate upon fermentation at higher temperatures than the progenitor strain.  
     
     
         31 . The improved  P. citrea  strain of  claim 30 , wherein the progenitor strain is capable of producing 2,5-diketo-D-gluconate from a carbon source.  
     
     
         32 . The improved  P. citrea  strain of  claim 30 , wherein the progenitor strain is a recombinant strain that comprises a heterologous nucleic acid sequence encoding a 2,5-diketo-D-gluconate reductase and is capable of converting 2,5-diketo-D-gluconate to 2-keto-L-gluconic acid.