title: Genetic, enzymatic and metabolite profiling of the Lactobacillus casei group reveals strain biodiversity and potential applications for flavour diversification.
abstract: OBJECTIVE
  The Lactobacillus casei group represents a widely explored group of lactic acid bacteria, characterized by a high level of biodiversity. In this study, the genetic and phenotypic diversity of a collection of more than 300 isolates of the Lact. casei group and their potential to produce volatile metabolites important for flavour development in dairy products, was examined.
  
  
  RESULTS
  Following confirmation of species by 16S rRNA PCR, the diversity of the isolates was determined by pulsed-field gel electrophoresis. The activities of enzymes involved in the proteolytic cascade were assessed and significant differences among the strains were observed. Ten strains were chosen based on the results of their enzymes activities and they were analysed for their ability to produce volatiles in media with increased concentrations of a representative aromatic, branched chain and sulphur amino acid. Volatiles were assessed using gas chromatography coupled with mass spectrometry. Strain-dependent differences in the range and type of volatiles produced were evident.
  
  
  CONCLUSIONS
  Strains of the Lact. casei group are characterized by genetic and metabolic diversity which supports variability in volatile production.
  
  
  CONCLUSIONS
  This study provides a screening approach for the knowledge-based selection of strains potentially enabling flavour diversification in fermented dairy products.
authors.affiliation: Department of Food Bioscience, Teagasc Food Research Centre, Moorepark, Fermoy, Ireland.|School of Microbiology, University College Cork, Cork, Ireland.
authors.forename: E
authors.initials: E
authors.lastname: Stefanovic
authors.affiliation: Department of Food Bioscience, Teagasc Food Research Centre, Moorepark, Fermoy, Ireland.
authors.forename: K N
authors.initials: KN
authors.lastname: Kilcawley
authors.affiliation: Department of Food Bioscience, Teagasc Food Research Centre, Moorepark, Fermoy, Ireland.
authors.forename: M C
authors.initials: MC
authors.lastname: Rea
authors.affiliation: School of Microbiology, University College Cork, Cork, Ireland.
authors.forename: G F
authors.initials: GF
authors.lastname: Fitzgerald
authors.affiliation: Department of Food Bioscience, Teagasc Food Research Centre, Moorepark, Fermoy, Ireland.
authors.forename: O
authors.initials: O
authors.lastname: McAuliffe
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D044822:Biodiversity; D043302:Cultured Milk Products / Q000382:microbiology*; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D005285:Fermentation; D005421:Flavoring Agents / Q000378:metabolism*; D007777:Lactobacillaceae / Q000235:genetics; D007780:Lacticaseibacillus casei / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction / Q000379:methods; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; D005421:Flavoring Agents; D012336:RNA, Ribosomal, 16S
keywords: Lactobacillus; PFGE; dairy; diversity; proteinase