Enzymes capable of catalyzing n-mannitol formation from n-fructose or n-fructose 6-phosphate have been identified in various microorganisms. Substrate and coenzyme specificity have been established in only a few instances, but there appear to be enzymes, dependent upon nicotinamide adenine dinucleotide and upon nicotinamide adenine dinucleotide phosphate, which reduce fructose directly to manni...