Mannitol production by Lactobacillus fermentum CRL 573 using sugar cane molasses as substrate

MARÍA JOSÉ FORNAGUERA; RAÚL RAYA; FERNANDA MOZZI

Copenague, Denmark

Simposio; Food Micro 2010 -22nd ICFMH symposium; 2010

International Committee on Food Microbiology and Hygiene

  n the last years, the use of sugar alcohols or low-calorie sugars in light and diabetic food products has intensified due to consumers’ demands for healthier functional foods. In this context, industrial production of mannitol has markedly increased worldwide and new alternatives to its chemical production have been sought. Thus, mannitol synthesis by heterofermentative lactic acid bacteria (LAB) has become a promising alternative to synthesize this compound to be used as food additive or produced in situ in fermented foods. In this work, the production of mannitol by Lactobacillus fermentum CRL573 using sugar cane molasses, an economic by-product from the sugar cane industry, as carbohydrate source was evaluated under different culture conditions. Free-pH fermentations using modified MRS containing different molasses concentration (3.0, 5.0, and 7.5%, w/v) at 37°C were carried out statically for 24 h. Controlled-pH batch fermentations at values of 4.0, 5.0 and 6.0 were also assayed. Cell viability (CFU/ml), sugar consumption, and organic acids and mannitol production (HPLC) were determined. The highest mannitol synthesis (30.7 g/l and Yp/x= 83.2%) by L. fermentum CRL 573 was achieved with 7.5% (w/v) of molasses at 37°C after 24 h during free-pH conditions. In controlled-pH fermentations, slightly higher amounts of mannitol (pH 6.0= 37.1 g/l, Yp/x 86.5%; pH 5.0= 34.5 g/l, Yp/x= 77.1%) respect to free-pH cultures were attained. No cell growth was observed at pH 4.0. Our studies show that mannitol can be successfully produced by L. fermentum CRL573 using sugar cane molasses as sugar source.