title: Characterization and application of an optical sensor for quantification of dissolved O2 in shake-flasks.
abstract: On-line measurement of dissolved O2 in shake-flasks was realized via immobilized sensor spots containing a fluorophore with an O2-dependent luminescent decay time. An unaffected sensor signal during 80 autoclaving cycles suggests multi-usage of sensor equipped shake-flasks. The sensor had a response time of 6 s. Quantification of gas-liquid mass transfer revealed maximum kLa values of 150 h(-1), from which maximum O2 transfer capacity of 33 mM h(-1) was calculated. Liquid volume and shaking frequency have a strong influence on kLa. Exemplified by cultivations of Corynebacterium glutamicum the importance of shaking rate for O2 supply of bacterial cultures is shown. Sampling of microbial cultures with intermittent shaking of a few minutes can cause O2 limitation. Based on the results of this work a simple and straightforward tool is now available for accurate O2 sensing in shake-flasks, which are widely used in microbial cultivations.
authors.affiliation: Biochemical Engineering, Saarland University Am Stadtwald, 66123 Saarbrücken, Germany. c.wittmann@mx.uni-saarland.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Wittmann
authors.forename: Hyung Min
authors.initials: HM
authors.lastname: Kim
authors.forename: Gernot
authors.initials: G
authors.lastname: John
authors.forename: Elmar
authors.initials: E
authors.lastname: Heinzle
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D003352:Corynebacterium / Q000378:metabolism; D004867:Equipment Design; D005336:Fiber Optic Technology / Q000295:instrumentation* / Q000379:methods; D005456:Fluorescent Dyes; D005471:Fluoroscopy / Q000295:instrumentation / Q000379:methods; D010100:Oxygen / Q000032:analysis* / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000295:instrumentation* / Q000379:methods
chemical_list: D005456:Fluorescent Dyes; D010100:Oxygen