title: Mannitol production by heterofermentative Lactobacillus reuteri CRL 1101 and Lactobacillus fermentum CRL 573 in free and controlled pH batch fermentations.
abstract: Certain lactic acid bacteria, especially heterofermentative strains, are capable to produce mannitol under adequate culture conditions. In this study, mannitol production by Lactobacillus reuteri CRL 1101 and Lactobacillus fermentum CRL 573 in modified MRS medium containing a mixture of fructose and glucose in a 6.5:1.0 ratio was investigated during batch fermentations with free pH and constant pH 6.0 and 5.0. Mannitol production and yields were higher under constant pH conditions compared with fermentations with free pH, the increase being more pronounced in the case of the L. fermentum strain. Maximum mannitol production and yields from fructose for L. reuteri CRL 1101 (122 mM and 75.7 mol%, respectively) and L. fermentum CRL 573 (312 mM and 93.5 mol%, respectively) were found at pH 5.0. Interestingly, depending on the pH conditions, fructose was used only as an alternative external electron acceptor or as both electron acceptor and energy source in the case of the L. reuteri strain. In contrast, L. fermentum CRL 573 used fructose both as electron acceptor and carbon source simultaneously, independently of the pH value, which strongly affected mannitol production by this strain. Studies on the metabolism of these relevant mannitol-producing lactobacilli provide important knowledge to either produce mannitol to be used as food additive or to produce it in situ during fermented food production.
authors: Centro de Referencia para Lactobacilos (CERELA)-CONICET, Chacabuco 145, San Miguel de Tucumán, Argentina.
authors: Cecilia
authors: C
authors: Rodríguez
authors: Tom
authors: T
authors: Rimaux
authors: María José
authors: MJ
authors: Fornaguera
authors: Gino
authors: G
authors: Vrancken
authors: Graciela Font
authors: GF
authors: de Valdez
authors: Luc
authors: L
authors: De Vuyst
authors: Fernanda
authors: F
authors: Mozzi
mesh_terms: D003470:Culture Media / Q000378:metabolism; D005285:Fermentation; D005632:Fructose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D052197:Limosilactobacillus fermentum / Q000378:metabolism*; D052200:Limosilactobacillus reuteri / Q000378:metabolism*; D008353:Mannitol / Q000378:metabolism*
chemical_list: D003470:Culture Media; D005632:Fructose; D008353:Mannitol