I'm encountering a persistent problem with cell count stagnation in my fed- batch process with CHO S cell line. Initially, after seeding on day 5-6, the cell count reaches 6-8 million cells/ml, but thereafter, it remains stagnant throughout the process despite daily feeding at 5% of the total volume. Additionally, metabolite analysis indicates a glucose level of 3.94 g/L, ruling out glucose deficit as the cause. The glutamine level was found to be 0.14mmol/L. I was suspecting that the glutamine level is the reason for stagnant in cell growth in the bioreactor.
The bioreactor parameters are as follows:-
1)Working volume - 80 ml
2)pH- 7.0
3)Temp- 37 degree Celsius
4) DO- 60% (managed by pure O2)
5) Stirrer - 333rpm (as per the tip speed calculation of 0.5m/s)
Any insights or suggestions on potential factors causing this stagnation would be greatly appreciated.
Thank you!!
D M Naveen Giri - My CHO Cells Aren't Growing in the Bioreactor!
I'm running a fed-batch process for CHO cells in a 250mL Biostream bioreactor with a working volume of 80mL. The key parameters are:
- Impeller diameter: 6mm
- Target tip speed: 0.5 m/s (achieved at 323rpm)
- Air flow: 10 mL/min
- DO: 60%
- pH control: CO2 and sodium bicarbonate
- Cells: Adapted to CD media Dynamis
- Seeding density: 0.5 million cells/mL (viability >98%)
- Temperature: 37°C
The Problem:
Cells aren't growing well in the bioreactor. Even at a higher tip speed (1.0 m/s, 640rpm), there's no improvement. Compared to shake flasks (130rpm) where cell counts reach 38 million/mL, the bioreactor only reaches 5 million/mL.
Question:
What could be causing the low cell growth in the bioreactor? How can I optimize the next batch?
Additional Information:
- kLa is within the recommended range for CHO cells.
- I'm looking for troubleshooting tips, especially simple or overlooked issues.
Expert Advice Needed:
Can you help me identify the root cause of the problem and suggest the best impeller rpm for the next batch?
try static mode in the bioreactor; since the air input is creating required turbulance, it shud suffice.
D M Naveen Giri The cells are in suspension mode so I think the cells are bound to be in continuous motion for equal distribution of nutrients. If the cells attain static mode the growth will be hindered.
since aeration is provided ; the turbulance is enough, the impeller can be static.
Hey, feel free to contact us. We have experience on solving these kind of challenges. Best, Fabian
https://www.capricorn-scientific.com/CHOventure?utm_source=newsletter&utm_medium=organic&utm_campaign=cho_mailshot_27-05-24
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