title: Glucolytic fingerprinting reveals metabolic groups within the genus Bifidobacterium: an exploratory study.
abstract: Microorganisms of the genus Bifidobacterium are inhabitants of diverse niches including the digestive tract of humans and animals. The species Bifidobacterium adolescentis, Bifidobacterium animalis, Bifidobacterium bifidum, Bifidobacterium breve and Bifidobacterium longum have qualified presumption of safety status granted by EFSA and several strains are considered probiotic, and are being included in functional dairy fermented products. In the present work we carried out a preliminary exploration of general metabolic characteristics and organic acid production profiles of a reduced number of strains selected from these and other species of the genus Bifidobacterium. The use of resting cells allowed obtaining metabolic fingerprints without interference of metabolites accumulated during growth in culture media. Acetic acid was the most abundant organic acid formed per mol of glucose consumed (from 1.07 ± 0.03 to 1.71 ± 0.22 mol) followed by lactic acid (from 0.34 ± 0.06 to 0.90 ± 0.12 mol), with moderate differences in production among strains; pyruvic, succinic and formic acids were also produced at considerably lower proportions, with variability among strains. The acetic to lactic acid ratio showed lower values in stationary phase as regard to the exponential phase for most, but not all, the microorganisms; this was due to a decrease in acetic acid molar proportions together with increases of lactic acid proportions in stationary phase. A linear discriminant analysis allowed to cluster strains into species with 51-100% probability, evidencing different metabolic profiles, according to the relative production of organic acids from glucose by resting cells, of microorganisms collected at the exponential phase of growth. Looking for a single metabolic marker that could adequately discriminate metabolic groups, we found that groups established by the acetic to lactic acid ratio fit well with differences previously evidenced by the discriminant analysis. The proper establishment of metabolic groups within the genus Bifidobacterium could help to select the best suited probiotic strains for specific applications.
authors.affiliation: 1 Probiotics and Prebiotics Group, Department of Microbiology and Biochemistry of Dairy Products, Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas (IPLA-CSIC), Paseo Rio Linares s/n, 33300 Villaviciosa, Asturias, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Rios-Covián
authors.affiliation: 1 Probiotics and Prebiotics Group, Department of Microbiology and Biochemistry of Dairy Products, Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas (IPLA-CSIC), Paseo Rio Linares s/n, 33300 Villaviciosa, Asturias, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Sánchez
authors.affiliation: 2 Scientific and Technical Facilities, IPLA-CSIC, Paseo Rio Linares s/n, 33300 Villaviciosa, Asturias, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Cuesta
authors.affiliation: 3 Scientific and Technical Facilities, University of Oviedo, Fernando Bonguera s/n, 33006 Oviedo, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Cueto-Díaz
authors.affiliation: 2 Scientific and Technical Facilities, IPLA-CSIC, Paseo Rio Linares s/n, 33300 Villaviciosa, Asturias, Spain.
authors.forename: A M
authors.initials: AM
authors.lastname: Hernández-Barranco
authors.affiliation: 1 Probiotics and Prebiotics Group, Department of Microbiology and Biochemistry of Dairy Products, Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas (IPLA-CSIC), Paseo Rio Linares s/n, 33300 Villaviciosa, Asturias, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Gueimonde
authors.affiliation: 1 Probiotics and Prebiotics Group, Department of Microbiology and Biochemistry of Dairy Products, Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas (IPLA-CSIC), Paseo Rio Linares s/n, 33300 Villaviciosa, Asturias, Spain.
authors.forename: C G
authors.initials: CG
authors.lastname: De los Reyes-Gavilán
mesh_terms: D001644:Bifidobacterium / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media / Q000378:metabolism; D005285:Fermentation; D005947:Glucose / Q000378:metabolism*; D019344:Lactic Acid / Q000378:metabolism; D019936:Probiotics / Q000378:metabolism
chemical_list: D003470:Culture Media; D019344:Lactic Acid; D005947:Glucose
keywords: Bifidobacterium; acetic acid; lactic acid; metabolic group; resting cells