title: Critical evaluation of sampling techniques for residual glucose determination in carbon-limited chemostat culture of Saccharomyces cerevisiae.
abstract: In this paper, three sampling techniques for rapid quenching of cellular metabolism and subsequent separation of cells from fermentation broth are compared: (i) quick freezing of fermentation broth directly in liquid nitrogen; (ii) quenching metabolism by exposing the fermentation broth to stainless steel beads (4-mm diameter) in a filter syringe precooled to -18 degrees C; and (iii) withdrawal of the filtrate through a 0.45 microm filter attached to a syringe and a needle inserted directly into the fermentor. It was concluded that use of liquid nitrogen as a quenching method to rapidly arrest cellular metabolism, for quantitative analysis of extracellular glucose, is not a very reliable method and that the filter syringe steel beads work very well.
authors.affiliation: Kluyver Laboratory for Biotechnology, 67 Julianalaan, 2628BC Delft, The Netherlands. M.Mashego@TNW.TUDelft.nl
authors.forename: M R
authors.initials: MR
authors.lastname: Mashego
authors.forename: W M
authors.initials: WM
authors.lastname: van Gulik
authors.forename: J L
authors.initials: JL
authors.lastname: Vinke
authors.forename: J J
authors.initials: JJ
authors.lastname: Heijnen
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D003080:Cold Temperature; D003470:Culture Media / Q000032:analysis* / Q000528:radiation effects; D005615:Freezing; D005947:Glucose / Q000032:analysis* / Q000378:metabolism*; D015203:Reproducibility of Results; D012440:Saccharomyces / Q000737:chemistry / Q000254:growth & development* / Q000378:metabolism* / Q000528:radiation effects; D012680:Sensitivity and Specificity
chemical_list: D003470:Culture Media; D005947:Glucose