Mannitol production by Lactobacillus coryniformis subsp. coryniformis CRL 1001 and Lactobacillus fermentum CRL 573

FERNANDA MOZZI; MARÍA JOSÉ FORNAGUERA; GINO VRANCKEN; TOM RIMAUX; CECILIA RODRÍGUEZ; GRACIELA FONT DE VALDEZ; RAÚL RAYA; LUC DE VUYST

Egmond aan Zee, The Netherlands

Simposio; 9th Symposium Lactic Acid Bacteria. Health, Evolution and Systems Biology; 2008

Federation of European Microbiological Societies. The Netherlands Society for Microbiology

Mannitol production by Lactobacillus coryniformis subsp. coryniformis CRL1001 and Lactobacillus fermentum CRL573 Fernanda Mozzi1, María José Fornaguera1, Gino Vrancken2, Cecilia Rodríguez1, Graciela Font de Valdez1, Raúl Raya1 and Luc De Vuyst2 1Centro de Referencia para Lactobacilos (CERELA-CONICET), Chacabuco 145, 4000-Tucumán, Argentina. 2Research Group of Industrial Microbiology and Food Biotechnology (IMDO), Department of Applied Biological Sciences and Engineering, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium. Mannitol is a sugar alcohol widely spread in nature that has several applications in the food, pharmaceutical and medical industries. It has been claimed to have health-promoting effects as antioxidant and as non-metabolizable low-calorie sweetener, being applicable for diabetic food products. In the last years, mannitol production by lactic acid bacteria (LAB) has been approached as an alternative to its chemical industrial production. Thus, mannitol could be used as food additive or be produced in situ by LAB. In this work, mannitol production by Lactobacillus coryniformis subsp. coryniformis CRL1001 and L. fermentum CRL573, previously selected for their ability to synthesize mannitol, was evaluated under varied culture conditions. The effect of different carbon sources (fructose, fructose/glucose, sucrose and sugar cane molasses), sugar concentrations (1.0-10.0%, w/v), incubation temperatures (30 and 37°C) and fermentation periods (up to 48 h) on mannitol synthesis was studied. Both LAB strains produced mannitol from all carbon sources assayed except when using fructose alone. Maximum mannitol production (38.4 g/l and Y(mmol%)= 84.7 for L. coryniformis subsp. coryniformis CRL1001 and 45.9 g/l and Y(mmol%)= 67.9 for L. fermentum CRL573) were obtained using sugar cane molasses (7.5%) at 37°C after 48 h. When agitation was applied, an increase in mannitol production and yield (43.6 g/l and Y(mmol%)= 98.9) was observed only for the strain CRL1001. The mdh gene encoding mannitol-2-dehydrogenase (MDH) was amplified by PCR for L. coryniformis subsp. coryniformis CRL1001; its sequence analysis revealed 99-100% identity at the DNA level with the mdh genes of L. reuteri strains.