title: The stimulating effect of a harsh environment on the bacteriocin activity by Enterococcus faecium RZS C5 and dependency on the environmental stress factor used.
abstract: Bacteriocin production by Enterococcus faecium RZS C5 occurs in a growth-associated way but is generally switched off in the very early growth phase. The influence of environmental stress on the bacteriocin production kinetics by E. faecium RZS C5 was analysed at a controlled temperature of 35 degrees C and constant pH 6.5. The effect of environmental stress on bacteriocin production was depending on the type of stress applied. Oxidative stress did not interfere with cell growth or bacteriocin activity. In contrast, salt stress decreased both the cell growth and the specific bacteriocin production. Nevertheless, moderate levels of sodium chloride improved bacteriocin activity because they increased the biomass concentration at which bacteriocin production was switched off. Environmental stress due to limitations in sugar or complex nutrients did not affect the early shut-off mechanism or the specific bacteriocin production. However, bacteriocin stability decreased or increased at low levels of sugar or complex nutrients, respectively.
authors.affiliation: Research Group of Industrial Microbiology, Fermentation Technology and Downstream Processing (IMDO), Department of Applied Biological Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Leroy
authors.forename: Sarah
authors.initials: S
authors.lastname: Vankrunkelsven
authors.forename: Johan
authors.initials: J
authors.lastname: De Greef
authors.forename: Luc
authors.initials: L
authors.lastname: De Vuyst
mesh_terms: D001430:Bacteriocins / Q000096:biosynthesis*; D002241:Carbohydrates / Q000494:pharmacology*; D002611:Cheese / Q000382:microbiology; D016984:Enterococcus faecium / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D005285:Fermentation; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008954:Models, Biological; D012965:Sodium Chloride / Q000494:pharmacology*; D013696:Temperature
chemical_list: D001430:Bacteriocins; D002241:Carbohydrates; D012965:Sodium Chloride