Manufacturing of xylitol using recombinant microbial hosts

A method for production of xylitol from a recombinant microbial host, wherein said method comprises:

• a) growing an arabitol-producing yeast or an arabitol-producing fungus under conditions that provide for synthesis of said xylitol, wherein said arabitol-producing yeast or said arabitol-producing fungus has been modified to synthesize xylitol as an end product in a single fermentation when grown on D-arabitol or a carbon source that the unmodified arabitol-producing yeast or unmodified arabitol-producing fungus utilized for D-arabitol biosynthesis, said carbon source being other than D-xylose, D-xylulose, mixtures of D-xylose and D-xylulose, and polymers and oligomers containing D-xylose or D-xylulose as major components under conditions that provide for synthesis of said xylitol wherein before said modification said host produced D-arabitol but did not utilize said D-arabitol for the synthesis of xylitol, and wherein said host has been transformed with a DNA encoding a D-xylulose forming D-arabitol dehydrogenase (E.C. 1.1.1.11) and with a DNA encoding xylitol dehydrogenase (E.C. 1.1.1.9);
• and
• b) recovering said xylitol produced in step a.