title: Application of flow cytometry to segregated kinetic modeling based on the physiological states of microorganisms.
abstract: Flow cytometry (FC) has been introduced to characterize and to assess the physiological states of microorganisms in conjunction with the classical plate-counting method. To show the applicability of the technique, in particular for the development of kinetic models, pure culture fermentation experiments were followed over time, using both prokaryotic (Lactobacillus hilgardii) and eukaryotic (Saccharomyces cerevisiae) microorganisms growing in standard culture media (MRS and YPD). The differences observed between the active and viable cells determined by FC and CFU, respectively, allowed us to determine that a large number of cells were in a viable but nonculturable (VBNC) state, which resulted in a subpopulation much larger than the damaged-cell (double-stained) subpopulation. Finally, the determination of the evolution of viable, the VBNC, and the dead cells allowed us to develop a segregated kinetic model to describe the yeast and the bacteria population dynamics and glucose consumption in batch cultures. This model, more complete than that which is traditionally used, based only on viable cell measurements, describes better the behavior and the functionality of the cultures, giving a deeper knowledge in real time about the status and the course of the bioprocesses.
authors.affiliation: Department of Chemical Engineering and Environmental Technology, Faculty of Chemistry, University of Oviedo, C/Julián Clavería s/n, 33071 Oviedo, Spain.
authors.forename: Covadonga
authors.initials: C
authors.lastname: Quirós
authors.forename: Mónica
authors.initials: M
authors.lastname: Herrero
authors.forename: Luis A
authors.initials: LA
authors.lastname: García
authors.forename: Mario
authors.initials: M
authors.lastname: Díaz
mesh_terms: D005285:Fermentation; D005434:Flow Cytometry / Q000379:methods*; D005947:Glucose / Q000378:metabolism; D007778:Lactobacillus / Q000254:growth & development*; D008954:Models, Biological; D011157:Population Dynamics; D012441:Saccharomyces cerevisiae / Q000254:growth & development*
chemical_list: D005947:Glucose