I'm currently experiencing overfoaming in my E.coli culture. My cells are used to produce a recombinant protein. The basic cell strain is BL-21 DE3. After changing my carbon source brand i am seeing different behaviour in growth and expression (more growth less expression) of my cells. Another observation is that i have more foaming compared to my previous fermentations. Also, I am witnessing an escalation in biomass production, optical density after induction of my cells and etc. I am assuming that my new carbon source have better purity hence shifts my cells towards growth and cell division rather than protein expression. The least of Glucose i have measured in my culture after induction is 1 g/L which is slightly higher than what it should be. Any thoughts how to define what is going on with my cultivation?
Hi,
usually, the more foaming in E.coli culture the better they feel :)
It could be that new carbon source is somehow rich in glucose, which prevents lac operon activation. I would play around with IPTG/lactose concentration. Maybe one just need to add a little bit more. Decreasing temperature may also help with excessive cell division. From my experience, every tryptone/yeast extract brand needs individual optimization.
Good luck!
Kindly check this publication https://link.springer.com/article/10.1007/BF02391583
Also check https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4641145/
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