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
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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


Specifications Oxygen pH*
* 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 range 0 - 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 ± 0.05 % O2 at 0.2 % O2
± 0.4 % O2 at 20.9 % 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.)
Measurement temperature range from + 5 to + 50 °C
Response time (t90)*** at 25 °C: < 60 sec.
Compatibility Aqueous solutions, ethanol (max. 10 % v/v), methanol (max. 10 % v/v), pH 2 - 10
Cross-sensitivity Typically no cross-sensitivity Reduced to ionic strength (salinity); a high concentration of small fluorescent molecules in the visible range can interfere
Calibration Pre-calibrated
  Disposables are delivered irradiated.

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Why It Is Important to Measure Different Parameters Online in Shake Flasks Interpreting SFR vario Online Data Gathered in Plant Cell Suspension Culture Characterizing CHO Cell Lines with SFR vario SFR vario Discriminates Good from Bad in Shake Flasks Optical Biomass Measurements in a Salvia fruticosa Cell Culture The Application of the SFR Shake Flask Reader in Teaching at the Esslingen University of Applied Sciences CO2, Oxygen and Biomass Monitoring in E. coli Shake Flask Culture New Device for Biomass Monitoring in Shake Flask Culture A New Method for Predicting Oxygen Supply during Aerobic Growth Online Monitoring of S. cerevisiae Culture with the SFR vario Characterization of Microbial Growth Profiles Insect Cell Cultivation in Orbitally Shaken Flasks with Sensors Accurate Insight into Oxygen Content of Shake Cultures Development of a Partly Controllable System at Shake Flask Scale Development of a Shaken Scale-Down Model Online Monitoring of Glucose, pH, and DO in Shake Flask Culture Design of Experiment (DoE) for Fed-batch Process Development in Shaken Cultures Improved Time Resolved KPI and Strain Characterization of Multiple Hosts in Shake Flasks Using Advanced Online Analytics and Data Science Continuous optical in-line glucose monitoring and control in CHO cultures contributes to enhanced metabolic efficiency while maintaining darbepoetin alfa product quality Methods for Oxygenation of Continuous Cultures of Brewer’s Yeast, Saccharomyces cerevisiae Phosphate limitation alleviates the inhibitory effect of manganese on itaconic acid production by Aspergillus terreus High cell density cultivation of E. coli in shake flasks for the production of recombinant proteins Determination of culture design spaces in shaken disposable cultivation systems for CHO suspension cell cultures Robustness and Plasticity of Metabolic Pathway Flux among Uropathogenic Isolates of Pseudomonas aeruginosa Predictive Monitoring of Shake Flask Cultures with Online Estimated Growth Models Online measurement of dissolved oxygen in shake flask to elucidate its role on caffeine degradation by Pseudomonas sp. HEK293 Cell-Based Bioprocess Development at Bench Scale by Means of Online Monitoring in Shake Flasks (RAMOS and SFR) Methanol Independent Expression by Pichia Pastoris Employing Derepression Technologies Antifoam addition to shake flask cultures of recombinant Pichia pastoris increases yield The metabolic potential of Escherichia coli BL21 in defined and rich medium Optical device for parallel online measurement of dissolved oxygen and pH in shake flask cultures A shaken disposable bioreactor system for controlled insect cell cultivations at milliliter-scale Effects of hypoxic culture conditions on umbilical cord-derived human mesenchymal stem cells Conversion of Corynebacterium glutamicum from an aerobic respiring to an aerobic fermenting bacterium by inactivation of the respiratory chain Oxygen supply in disposable shake-flasks: prediciton of oxygen transfer rate, oxygen saturation and maximum cell concentration during aerobic growth Noninvasive online biomass detector system for cultivation in shake flasks Application 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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