Sorbitol dehydrogenase, gene encoding the same and use thereof

Abstract

The present invention provide a gene encoding D-sorbitol dehydrogenase (SLDH), a method for producing SLDH by culture of a host cell transformed with a vector expressing this gene and a method for producing L-sorbose or 2-keto-L-gulonic acid (2KLGA) using the culture. 2KLGA is an important intermediate for the production of L-ascorbic acid. Therefore, the present invention also provides a method for producing L-ascorbic acid from the 2KLGA obtained by the above-mentioned method.

1 - 22 . (Cancelled)  
     
     
         23 . A host cell comprising one or more expression vector(s) comprising separately or collectively DNA encoding sorbitol dehydrogenase (SLDH), a DNA encoding sorbose dehydrogenase (SLDH), a DNA encoding sorbosone dehydrogenase (SNDH).  
     
     
         24 . The host cell of  claim 23 , which contains an expression vector which comprises a DNA encoding SLDH, and an expression vector comprising a DNA encoding SDH and SNDH.  
     
     
         25 . The host cell of  claim 23 , which contains an expression vector comprising a DNA encoding SLDH, SDH and SNDH.  
     
     
         26 . The host cell of  claim 23 , wherein said host cell is  Escherichia.    
     
     
         27 . The host cell of  claim 23 , wherein said host cell is  Pseudomonas.    
     
     
         28 . The host cell of  claim 23 , wherein said host cell is  Pseudogluconobacter.    
     
     
         29 . The host cell of  claim 23 , wherein said host cell is  Gluconobacter.    
     
     
         30 . The host cell of  claim 23 , wherein said host cell is  Acetobacter.    
     
     
         31 . A method for producing 2-keto-L-gluconic acid, comprising: 
 (a) culturing in a suitable medium a transformant comprising at least one expression vector comprising separately or collectively all of a DNA encoding sorbitol dehydrogenase (SLDH), a DNA encoding sorbose dehydrogenase (SLDH), a DNA encoding sorbosone dehydrogenase (SNDH); and    (b) bringing D-sorbitol into contact with the obtained culture or a treated product thereof.    
     
     
         32 . The method of  claim 31 , wherein said transformant comprises an expression vector which comprises a DNA encoding SLDH, and an expression vector comprising a DNA encoding SDH and SNDH.  
     
     
         33 . The method of  claim 31 , wherein said transformant comprises an expression vector comprising a DNA encoding SLDH, SDH and SNDH.  
     
     
         34 . The method of  claim 31 , wherein said transformant is derived from a host cell belonging to  Pseudomonas.    
     
     
         35 . The method of  claim 31 , wherein said SLDH is derived from  Gluconobacter.    
     
     
         36 . The method of  claim 31 , wherein said SLDH is dependent on NAD(P) + .  
     
     
         37 . The method of  claim 31 , wherein said host cell is  Escherichia.    
     
     
         38 . The method of  claim 31 , wherein said host cell is  Pseudomonas.    
     
     
         39 . The method of  claim 31 , wherein said host cell is  Pseudogluconobacter.    
     
     
         40 . The method of  claim 31 , wherein said host cell is  Gluconobacter.    
     
     
         41 . The method of  claim 31 , wherein said host cell is  Acetobacter.    
     
     
         42 . The method of  claim 31 , which is carried out in the presence of glycerol.