Bio-based method for making mannitol

Abstract

Mannitol is produced in a highly efficient fermentative method using Lactobacillus intermedius NRRL B-30560, or in a biochemical method using mannitol dehydrogenase isolated from this strain. Fructose serves as the primary carbon substrate in both the fermentative and biochemical conversions, but important secondary carbon sources include glucose, maltose, mannose and galactose. Mannitol is useful in the food, pharmaceutical, and medicine industries as a sweet-tasting bodying and texturing agent.

1 . A method for producing mannitol comprising: 
 a. cultivating mannitol dehydrogenase from the bacterium  Lactobacillus intermedius  NRRL B-30560 in a medium containing fructose as the primary carbon source under conditions suitable for the growth of said bacterium;    b. recovering mannitol from said medium.    
     
     
         2 . The method of  claim 1 , wherein said fermentation medium also comprises a secondary carbon source selected from the group consisting of glucose, maltose, mannose, raffinose galactose and starch with glucoamylase.  
     
     
         3 . The method of  claim 2 , wherein the secondary carbon source is mannose.  
     
     
         4 . The method of  claim 2 , wherein the secondary carbon source is initially present at a level of less than about 33% (w/w) of the total carbon source.  
     
     
         5 . The method of  claim 3 , wherein the mannose is initially present in a fructose : mannose weight ratio of about 2:1.  
     
     
         6 . The method of  claim 1 , wherein the pH in step (a) is controlled within the range of about 4.5-6.0.  
     
     
         7 . The method of  claim 1 , wherein the temperature in step (a) is at least about 25° C.  
     
     
         8 . The method of  claim 1 , wherein the temperature in step (a) is at least about 30° C.  
     
     
         9 . Substantially pure mannitol dehydrogenase isolated from  Lactobacillus intermedius  NRRL B-30560.