ARS | Publication request: Mannitol Dehydrogenase from Heterofermentative Lactic and Bacteria

Submitted to: United States Japan Natural Resources Protein Panel
Publication Type: Proceedings/Symposium
Publication Acceptance Date: November 15, 2003
Publication Date: October 1, 2003
Citation: Saha, B.C. 2003. Mannitol dehydrogenase from heterofermentative lactic and bacteria. In: Proceedings of the United States Japan Cooperative Program in Natural Resources Food and Agriculture Panel. 32nd Annual Meeting, Tsukuba, Ibaraki, Japan. p. 285-289.

Technical Abstract: Mannitol 2-dehydrogenase (MDH) catalyzes the NAD or NADP dependent reduction of fructose to mannitol and oxidation of mannitol to fructose. Some heterofermentative lactic acid bacteria (LAB) have the capacity to produce mannitol from fructose using MDH. Lactobacillus intermedius (NRRL B-3693), a heterofermentative LAB, was found to be an excellent producer of mannitol. The intracellular MDH from this bacterium was purified, characterized, and N-terminal amino acid sequence determined. The enzyme was optimally active at pH 5.5 and 35 deg C for reduction of fructose. Comparative properties of this enzyme to those from other heterofermentative LAB are presented. The reductive activity of the MDH from L. intermedius on fructose was 4.27 times greater with NADPH than NADH as cofactor. This is the first highly NADPH dependent MDH (EC 1.1.1.138) from a LAB. A brief review on the enzymatic conversion of mannitol from fructose using MDH is also presented. The MDH has great potential to be used in a single step conversion of fructose to mannitol if the cofactor NAD(P)H can be regenerated in an efficient way as the enzyme converts fructose to mannitol completely.