title: Conjugated Linoleic Acid Production by Bifidobacteria: Screening, Kinetic, and Composition.
abstract: Conjugated linoleic acids (CLA) are positional and geometric isomers of linoleic acid involved in a number of health aspects. In humans, CLA production is performed by gut microbiota, including some species of potential probiotic bifidobacteria. 128 strains of 31 Bifidobacterium species were screened with a spectrophotometric assay to identify novel CLA producers. Most species were nonproducers, while producers belonged to B. breve and B. pseudocatenulatum. GC-MS revealed that CLA producer strains yielded 9cis,11trans-CLA and 9trans,11trans-CLA, without any production of other isomers. Hydroxylated forms of LA were absent in producer strains, suggesting that the myosin-cross-reactive antigen (MCRA) protein that exerts hydratase activity is not involved in LA isomerization. Moreover, both CLA producer and nonproducer species bear a MCRA homologue. The strain B. breve WC 0421 was the best CLA producer, converting LA into 68.8% 9cis,11trans-CLA and 25.1% 9trans,11trans-CLA. Production occurred mostly during the lag and the exponential phase. For the first time, production and incorporation of CLA in biomass were assessed. B. breve WC 0421 stored CLA in the form of free fatty acids, without changing the composition of the esterified fatty acids, which mainly occurred in the plasmatic membrane.
authors.affiliation: Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy.
authors.forename: Stefano
authors.identifier: 0000-0003-0944-6677
authors.initials: S
authors.lastname: Raimondi
authors.affiliation: Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Amaretti
authors.affiliation: Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy.
authors.forename: Alan
authors.initials: A
authors.lastname: Leonardi
authors.affiliation: Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Quartieri
authors.affiliation: Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Gozzoli
authors.affiliation: Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy.
authors.forename: Maddalena
authors.initials: M
authors.lastname: Rossi
mesh_terms: D001644:Bifidobacterium / Q000378:metabolism*; D018533:Biomass; D002462:Cell Membrane / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D000069196:Gastrointestinal Microbiome / Q000502:physiology; D006801:Humans; D007536:Isomerism; D007700:Kinetics; D019787:Linoleic Acid / Q000378:metabolism*
chemical_list: D005230:Fatty Acids, Nonesterified; D019787:Linoleic Acid