Submitted to: Biotechnology and Bioengineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 20, 2002
Publication Date: April 11, 2003
Citation: SAHA, B.C., NAKAMURA, L.K. PRODUCTION OF MANNITOL AND LACTIC ACID BY FERMENTATION WITH LACTOBACILLUS INTERMEDIUS NRRL B-3693. BIOTECHNOLOGY AND BIOENGINEERING. 2003. V. 82. P. 864-871. Interpretive Summary: Mannitol, a naturally occurring sugar alcohol, is widely used in the food, pharmaceutical, medicine, and chemical industries. It is currently produced as a mixture of mannitol and sorbitol (another sugar alcohol) by high pressure hydrogenation of corn derived sugars at high temperature with a catalyst. This chemical process is inefficient. We screened 72 bacterial cultures from the ARS Culture Collection and found that one, Lactobacillus sp., is an excellent producer of mannitol from fructose. The bacterial strain has great potential to be used in commercial production of mannitol by fermentation. This research will benefit the wet corn milling industry by providing an environmentally friendly method to produce a value-added sugar alcohol widely used in the food, pharmaceutical, medicine, and chemical industries from corn derived sugar.
Technical Abstract: Lactobacillus intermedius B-3693 was selected as a good producer of mannitol from 9 strains (Lactobacillus brevis B-1836, L. buchneri B-1860, L. cellobiosus B-1840, L. fermentum B-1915, L. intermedius B-3693, Leuconostoc amelibiosum B-742, L. citrovorum B-1147, L. mesenteroides subsp. dextranicum B-1120, and L. paramesenteroides B-3471) that produced mannitol from fructose, after screening 72 bacterial strains. The bacterium produced mannitol, lactic acid, and acetic acid from fructose in pH-controlled batch fermentation. Typical yields of mannitol, lactic acid, and acetic acid from 250 g/L fructose were 0.70, 0.16, and 0.12 g, respectively per g of fructose. The fermentation time was greatly dependent on fructose concentration (from 20 h at 150 g/L to 136 h at 300 g/L) but the product yields were not dependent on fructose level. Fed-batch fermentation decreased the time of maximum mannitol production from fructose (300 g/L) from 136 h to 92 h. One-third of fructose could be replaced with glucose, maltose, galactose, mannose, raffinose, or starch with glucoamylase (simultaneous saccharification and fermentation, SSF) and two-thirds of fructose could be replaced with sucrose. L. intermedius B-3693 did not co-utilize lactose, cellobiose, glycerol, and xylose with fructose. It produced lactic acid (70.4 ± 0.6 g/L) and ethanol (36.2 ± 1.0 g/L) but no acetic acid from glucose (150 g/L). The bacterium produced 21.3 ± 0.6 g lactic acid, 10.5 ± 0.3 g acetic acid, and 4.7 ± 0.0 g ethanol per L of fermentation broth from dilute acid (15% solids, 0.5% H2SO4, 121 deg C, 1 h) pretreated enzyme (cellulase, beta-glucosidase) saccharified corn fiber hydrolyzate.