Submitted to: Applied Microbiology and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2006
Publication Date: 7/1/2006
Citation: Saha, B.C. 2006. A low-cost medium for mannitol production by Lactobacillus intermedius NRRL B-3693. Applied Microbiology and Biotechnology. 72:676-680.
Interpretive Summary: Mannitol, a naturally occurring alcohol, is widely used in the food, pharmaceutical, medicine, and chemical industries. It is currently produced as a 25/75 mixture of mannitol and sorbitol (another sugar alcohol) by high pressure hydrogenation of 50/50 fructose/glucose mixture (corn derived sugars) in an aqueous solution at high temperature with a catalyst. The chemical process is inefficient. One lactic acid bacterium from the ARS Culture Collection (Peoria, IL) was found to be an excellent producer of mannitol from fructose. A low-cost medium containing molasses and fructose syrup and corn steep liquor (by-product of corn wet-milling industries) has been developed for mannitol production by the bacterium. This medium has great potential to be used in commercial production of mannitol by fermentation.
Technical Abstract: The production of mannitol by Lactobacillus intermedius NNRL B-3693, using molasses as an inexpensive carbon source, was evaluated. The bacterium produced mannitol (104.4 ± 0.6 g/L) from molasses and fructose syrups (1:1; total sugars, 150 g/L; fructose:glucose, 4:1) in 16 h. Several kinds of inexpensive organic and inorganic nitrogen sources and corn steep liquor were evaluated for their potential to replace more expensive nitrogen sources derived from Bacto-peptone and yeast extract. Soy peptone D (5 g/L) and corn steep liquor (50 g/L) were found to be suitable substitutes for Bacto-peptone (5 g/L) and Bacto-yeast extract (5 g/L), respectively. The bacterium produced 104.8 ± 0.9 g mannitol from the molasses and fructose syrup (1:1, total sugars, 150 g/L; fructose:glucose, 4:1) in 22 h using a combination of soy peptone D (5 g/L) and corn steep liquor (50 g/L). This is the first report on the production of mannitol by fermentation using molasses and corn steep liquor.