Online Oxygen & pH Monitoring in Shake Flasks

Sensor Flask SFS

These single-use shake flasks made of polycarbonate have an oxygen and a pH sensor integrated at the bottom. The flasks are available in sizes from 125 mL to 5,000 mL volumes, with or without baffles. The sensors inside are irradiated and pre-calibrated, so the flasks are ready-to-use. The SFS can be read out with the SFR Shake Flask Reader or the SFR vario, for simultaneous online monitoring of oxygen, pH, OUR and (in case of the SFR vario) biomass. They are used with special clamps that align the integrated sensors with the reader optics.

  • Online monitoring of O2 & pH
  • Contactless measurement
  • Ready-to-use
  • Pre-calibrated sensor
  • For microbes & cell culture


Process Monitoring in Suspension-Adapted CHO Cell Cultures

The online measurement of dissolved oxygen concentration and pH in shaken bioreactors paves the way for proper scale down activities from bench-top stirred-tanks to smaller scales. Adjustment of shaking speed as a function of pO2 is now possible avoiding possible oxygen limitations at high cell densities. Even a simple pH readjustment by tuning the pCO2 in the incubator is feasible to optimize the output from simple experiments with shaken bioreactors.
Dr. Robert Puskeiler, Roche Diagnostics, Penzberg, Germany

Yeast & E. coli: Ensure Enough Oxygen Supply

S. cerevisiae grows on different sugars as carbon source. While growth on glucose and fructose is mainly fermentative, growth on galactose is mainly respirative. This leads to low oxygen concentration in the shake flasks. The accurately measured oxygen indicates the need to increase rotation frequency to avoid oxygen limitation.

High oxygen demand is typical for E. coli in its exponential phase. In the cultivation shown on the left, rotation speed had to be changed twice in order to avoid oxygen limitation. In addition, changes in the metabolism can be detected by measuring DO.

Schneider et al., University of Saarland, Saarbrücken, GermanyBioprocess Biosyst Eng., 33(5), 541 - 547, 2009


* provided Sensor Flasks are used without further handling in physiological solutions
**HP5 and LG1 sensors require different SFR versions
*** at 100 rpm & in cell culture media
Measurement range0 - 100 % O2

HP5: 5.5 - 8.0 pH**
LG1: 4.0 - 7.5 pH**

Resolution± 0.01 % O2 at 0.21 % O2
± 0.1 % O2 at 20.9 % O2
± 0.01 pH at pH = 7***
Accuracy± 0.4 % O2 at 20.9 % O2
± 0.5 % O2 at 0.2 % O2
± 0.1 pH at pH = 7 with one-point adjustment
± 0.2 pH at pH = 7 with pre-calibration
Drift< 0.01 % O2 per day
(sampling interval of 1 min.)
< 0.01 pH per day
(sampling interval of 1 min.)
Mesaurment temperature rangefrom + 5 to + 50 °C
Response time (t90)***at 25 °C: < 60 sec.
CompatibilityAqueous solutions, ethanol (max. 10 % v/v), methanol (max. 10 % v/v), pH 2 - 10
Cross-sensitivityTypically no cross-sensitivityReduced to ionic strength (salinity); a high concentration of small fluorescent molecules in the visible range can interfere
Disposables are delivered irradiated.

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Optical Biomass Measurements in a Salvia fruticosa Cell CultureThe Application of the SFR Shake Flask Reader in Teaching at the Esslingen University of Applied SciencesCO2, Oxygen and Biomass Monitoring in E. coli Shake Flask CultureNew Device for Biomass Monitoring in Shake Flask CultureA New Method for Predicting Oxygen Supply during Aerobic GrowthOnline Monitoring of S. cerevisiae Culture with the SFR varioCharacterization of Microbial Growth ProfilesAccurate Insight into Oxygen Content of Shake CulturesDevelopment of a Partly Controllable System at Shake Flask ScaleDevelopment of a Shaken Scale-Down ModelOnline Monitoring of Glucose, pH, and DO in Shake Flask CultureDesign of Experiment (DoE) for Fed-batch Process Development in Shaken CulturesMethanol Independent Expression by Pichia Pastoris Employing Derepression TechnologiesAntifoam addition to shake flask cultures of recombinant Pichia pastoris increases yieldThe metabolic potential of Escherichia coli BL21 in defined and rich mediumOptical device for parallel online measurement of dissolved oxygen and pH in shake flask culturesA shaken disposable bioreactor system for controlled insect cell cultivations at milliliter-scaleEffects of hypoxic culture conditions on umbilical cord-derived human mesenchymal stem cellsConversion of Corynebacterium glutamicum from an aerobic respiring to an aerobic fermenting bacterium by inactivation of the respiratory chainOxygen supply in disposable shake-flasks: prediciton of oxygen transfer rate, oxygen saturation and maximum cell concentration during aerobic growthNoninvasive online biomass detector system for cultivation in shake flasksApplication of an Online-Biomass Sensor in an Optical Multisensory Platform Prototype for Growth Monitoring of Biotechnical Relevant Microorganisms and Cell Lines in Single-Use Shake Flasks

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