title: Diversity in robustness of Lactococcus lactis strains during heat stress, oxidative stress, and spray drying stress.
abstract: In this study we tested 39 Lactococcus lactis strains isolated from diverse habitats for their robustness under heat and oxidative stress, demonstrating high diversity in survival (up to 4 log units). Strains with an L. lactis subsp. lactis phenotype generally displayed more-robust phenotypes than strains with an L. lactis subsp. cremoris phenotype, whereas the habitat from which the strains had been isolated did not appear to influence stress survival. Comparison of the stress survival phenotypes with already available comparative genomic data sets revealed that the absence or presence of specific genes, including genes encoding a GntR family transcriptional regulator, a manganese ABC transporter permease, a cellobiose phosphotransferase system (PTS) component, the FtsY protein, and hypothetical proteins, was associated with heat or oxidative stress survival. Finally, 14 selected strains also displayed diversity in survival after spray drying, ranging from 20% survival for the most robust strains, which appears acceptable for industrial application, to 0.1% survival for the least-tolerant strains. The high and low levels of survival upon spray drying correlated clearly with the combined robustness under heat and oxidative stress. These results demonstrate the relevance of screening culture collections for robustness under heat and oxidative stress on top of the typical screening for acidifying and flavor-forming properties.
authors.affiliation: Kluyver Center for Genomics of Industrial Fermentation, Delft, The Netherlands.
authors.forename: Annereinou R
authors.initials: AR
authors.lastname: Dijkstra
authors.forename: Meily C
authors.initials: MC
authors.lastname: Setyawati
authors.forename: Jumamurat R
authors.initials: JR
authors.lastname: Bayjanov
authors.forename: Wynand
authors.initials: W
authors.lastname: Alkema
authors.forename: Sacha A F T
authors.initials: SA
authors.lastname: van Hijum
authors.forename: Peter A
authors.initials: PA
authors.lastname: Bron
authors.forename: Jeroen
authors.initials: J
authors.lastname: Hugenholtz
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D056726:Genetic Association Studies; D014644:Genetic Variation; D018869:Heat-Shock Response; D013294:Lactococcus lactis / Q000302:isolation & purification / Q000502:physiology*; D018384:Oxidative Stress / Q000235:genetics; D010641:Phenotype; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System