My question relates to the excessive foam formation when auto inductive growth media is shaken at high rpms. Instead of having to buy a new agent, I wonder if there's a common agent that I could use to suppress foaming e.g. by adding silica oil? Any ideas?
Hi Toni, we sometimes use PEG400 (as crystallographers we always have PEGs in stock :o) - try some (1-5) droplets from a standard syringe/canule combination and shake your culture (180-220 rpm), to see, if it works for you. Good luck, Magdalena
I'm sorry for derailing this a little but out of true curiosity: why do you need such high rpm's so it tends to foam to begin with?
It foams because I'm using an auto inductive medium in baffled flasks. The high rpm is required to provide enough aeration for the cells to reach the high ODs that are possible with auto inductive medium. However, this is partially counteracted by the formation of foam which might decrease the accessibility of available oxygen by covering the air/liquid interface. So, preventing foam formation should help to optimise growth conditions to obtain more protein.
Hi Toni, we sometimes use PEG400 (as crystallographers we always have PEGs in stock :o) - try some (1-5) droplets from a standard syringe/canule combination and shake your culture (180-220 rpm), to see, if it works for you. Good luck, Magdalena
In some industrial fermentation, soy bean oil is added to fermentation media to prevent foam production. I guess you can try vegetable oil or any oil that is not toxic to bacterial.
Thanks for all your answers. To recap, avoid foam formation by adding either one of those agents:
- PEG400 (1-5 droplets)
- n-octanol (a drop or two)
- soy bean oil (vegetable oil)
I'll give it a go next time around.
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