6 replies to this topic

[c0ok1e]

Hi. I cultured my bacteria at 2 ml and got stationary phase at OD 1.398.

But when I cultured the bacteria at 1 liter culture, I seem to get slow growth after reaching OD 0.576

Will there be a difference in OD at stationary phase at different culture volume or is there something wring with my experiment? WHy is this happening?

Thanks

[GeorgeWolff]

Was "stationary pahse" based on growth curve - cell count or just time?

[c0ok1e]

Based on cell growth. I did the bacteria count before this. Even if its based on time, when I cultured 1 ml I cultured it for 2 days and it reached OD 1.something

WHile for the 1 liter I cultured it for 4 days already and its growing slow at 0.5something

Do you guys get this often?

[leelee]

could it have something to do with the size of the flask compared to the volume??
I know I get much better growth with my bacteria when the volume of the flask is about 4x the volume ,i.e. 250ml in a 1L flask, or even more, compared say 250ml in a 500ml flask. I was told it had something to do with oxygen availability?

[microgirl]

I'm pretty sure your problem is oxygen availability. When you only have 2 ml of culture in a pretty big tube (like a Falcon tube), it shakes really well and gets nicely oxygenated. When you have a liter of culture, you probably don't have it in an enormous container and don't shake it nearly as much - less oxygen, slower/less growth.

[GeorgeWolff]

You prob said this but was "stationary pahse" based on cell count in the larger (1 liter) volume?  you can assume the same dynamics tranlate from a smaller volume.

[KatieB]

OD can change dependant on the stage of bacterial growth, have you tried taking samples for OD analysis at different timepoints throughout its growth?
KT