[lupok2001]

Hi everybody!

I am currently working with methanotrophic bacteria and I have noticed that, regardless of how much methane I give them, they would not grow more than a certain value. My guess is that oxygen depletes. I could try to do some experiment to check this out, but some rough calculations can tell me if it is worth it. I would appreciate if somebody can have a look on what I have been thinking and, if necessary, be critical about it.

I am working with a fixed volume of 960ml, at an initial pressure of 0.96 atm. Oxygen is 21% of atmospheric air, so oxygen partial pressure is 21% of 0.96 atm = 0.20 atm. When I add methane, the pressure goes up to 1.2 atm. So methane partial pressure is 1.2 - 0.96 = 0.24 atm.

In my final mixture, by the perfect gas law, assuming a temperature of 298°K and R=0.082 atm L K^-1, there should be 9 mmoles of methane and 8 mmoles of oxygen.

The balanced equation of methane respiration is:
CH₄+2O₂ ---> CO₂+2H₂O

So I would assume that with 8 mmoles of oxygen only 4 mmoles of methane should be consumed, and I could verify it by measuring the leftover methane in my cultures.

Do you think it make sense or did I left something out?