Low temperature-induced viable but not culturable state of Ralstonia eutropha and its relationship to accumulated polyhydroxybutyrate

FEMS Microbiol Lett. 2016 Dec;363(23):fnw249. doi: 10.1093/femsle/fnw249. Epub 2016 Nov 2.


The culturability of Escherichia coli, Ralstonia eutropha and Bacillus subtilis after incubation in phosphate-buffered saline at either 5°C or 30°C was determined. The culturability of B. subtilis showed little dependence on temperature. The culturability of E. coli rapidly decreased at 30°C but remained almost constant at 5°C. In contrast, the culturability of R. eutropha decreased by three orders of magnitude at 5°C within 24 h but only moderately decreased (one order of magnitude) at 30°C. Remarkably, prolonged incubation of R. eutropha at 30°C resulted in a full recovery of colony forming units in contrast to only a partial recovery at 5°C. Ralstonia eutropha cells at 30°C remained culturable for 3 weeks while culturability at 5°C constantly decreased. The effect of temperature was significantly stronger in a polyhydroxybutyrate-negative mutant. Our data show that accumulated polyhydroxybutyrate has a cold-protective function and can prevent R. eutropha entering the viable but not culturable state.

Keywords: VBNC; polyhydroxybutyrate; survival; viable but not culturable.

MeSH terms

  • Bacillus subtilis / genetics
  • Bacillus subtilis / growth & development*
  • Cold Temperature*
  • Colony Count, Microbial
  • Cupriavidus necator / genetics
  • Cupriavidus necator / growth & development*
  • Escherichia coli / genetics
  • Escherichia coli / growth & development*
  • Hot Temperature
  • Hydroxybutyrates / metabolism*


  • Hydroxybutyrates