I have a question.
I have to grow some fresh water microalgae. With the CO2 injecting I will have pH displacements in the grow solution. I want to use a buffer as a phosphate source (K2HPO4 - KH2PO4 - pH 7). Is it a stupid idea? I imagine that the algae will absorb part of the two salts altering their concentration, thus altering their buffer power. Do you have any suggestions?
Hi there
It depends what is the optimal pH the algae grow
There are alternative buffers such as the "good" buffers which are non toxic and sometimes are not consumed by the algae
Other alternative is to supplement the algae with organic carbon instead of inorganic, some algae can use both sources (e.g glucose)
Hope this helps
Hi Leonardo
Thank you for the answer
The algae I’m using grow well with pH from 6,5 to 7,5
I know that I’m able to replace phosphate buffer with other synthetic buffer as HEPES, MOPS, MES, but some of them inhibit the algal grow ... I don’t know the reason..
Have you other suggests about my problem?
Stefano
Hi
For how long are you growing your algae?
The amounts of phosphate in growing media for optimal grow are really high. It you are planning to grow your algae for not too long, phosphate levels will be very similar at the end of the experiment.
There are , however, other changes that could affect the pH when you inject your CO2, the alkalinity of dissolved CO2 has a big buffering effect as well.
You could try and insert a pH probe and measure the pH continuously to see what is the equilibrium (without algae ) of your phsophate buffer plus CO2.
I would then test pH with the algae because all the O2 produced and then dissolved may change the carbonate/bicarbonate solubility and therefore equilibrium
I hope this helps
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