N2O does not react with water at all. With leaving cells I don't know what reaction can take place.We have tried also the solution without cells. It was acidified too.
The chamber is 6 cm diameter * 10 tall and just 7/8 cm are filled with solution.
approx. 250 ml liquid +
approx. 70 ml air
I don't believe 0,04% atmospheric CO2 can acidify from 7.4 to 5.5, even pressurising the chamber at 60 or 100 bar.
Do you mean that you haven't tried with N2
O only? I thought you did, when you asked about a pH increase with N2
O. If the CO2
is present as well, even if at low concentrations, you probably have to do with the "carbonic anhydrase" enzyme contained in the living cells, which converts CO2
It means that CO2
is rapidly absorbed from air and continuously removed from it.
In absence of cells you should be able to compute the pH from the CO2
pressure in the reactor. 0,04 % it's not so little significative, at 100 bar.