Conditional confined oscillatory dynamics of Escherichia coli strain K12-MG1655 in chemostat systems

  1. Lookup NU author(s)
  2. Dr Dana Ofiteru
  3. Dr Mariana Ferdes
  4. Dr Charles Knapp
  5. Professor David Graham
  6. Professor Vasile Lavric
Author(s)Ofiteru ID, Ferdes M, Knapp CW, Graham DW, Lavric V
Publication type Article
JournalApplied Microbiology and Biotechnology
Year2012
Volume94
Issue1
Pages185-192
ISSN (print)0273-2289
ISSN (electronic)1559-0291
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A series of batch and continuous-low experiments were performed to assess growth dynamics of Escherichia coli strain K12-MG1655 in bioreactors. Previous mathematical predictions and early experimental results had shown that confined oscillatory dynamics occur in reactor populations that relates to time-delayed “birth and group death” events within the population. New results are reported here that generally verify predictions of the model and show that confined oscillations occur from different initial conditions, but the character of oscillatory dynamics varies as a function of hydraulic retention time (HRT). Bioreactors were operated with HRTs ranging from 2.7 to 35 hours and, regardless of start-up conditions or the imposition of transient operational instabilities, highly patterned oscillations ultimately developed when HRT was between ~ 3 and 8 hr. However, outside of this range, reactor populations tended to form biofilms on the reactor walls (rather than discrete growth in the bulk solution) and stable oscillations were not seen in the bulk phase. This suggests that alternate operating “states” might exist in reactor populations with biofilm formation and non-homogenous spatial growth patterns dominating system behaviour at low and high HRTs. Although the model predicts a confined dynamic equilibrium, data here show that such dynamics only occur at mid-range HRTs because biofilm formation dominates system behaviour outside of this range.
PublisherHumana Press, Inc.
URLhttp://dx.doi.org/10.1007/s00253-011-3697-1
DOI10.1007/s00253-011-3697-1
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