Production of idoheptulosan from sedoheptulosan by microorganisms

Microbial production of idoheptulosan has been established using a two-stage fermentation system. Sedoheptulosan was first converted to 5-ketosedoheptulosan by a strain of Agrobacterium, 449-1, in a medium containing sorbitol as the energy source. After 4 d of cultivation, sedoheptulosan (100 g/l was almost completely converted to its 5-keto form. Many strains of Gluconobacter were also found to have the same oxidizing activity. Asymmetric reduction of 5-ketosedoheptulosan to idoheptulosan was performed with strains of Aureobacterium, Pseudomonas, Paracoccus, Micrococcus or soil isolates of coryneform bacteria. By incubating these bacteria with 5-ketosedoheptulosan in medium containing d-glucose as the hydrogen donor for reduction, 5-ketosedoheptulosan was converted specifically to idoheptulosan after 5 d. The overall yield of idoheptulosan was about 60% when soil isolate CF-987 was used. Other stereoisomers of idoheptulosan and other metabolites were not detected in the final broth of the strain.