I am monitoring the effect of algae on yeast growth, one of my parameters is the CO2 production rate. I would like to know the suitable method that will allow me to measure the CO2 while it is still in the incubator. I have no access to a risograph or a ROMAS. The displacement method isn't suitable either.
You may try using the Gravity analog CO2 gas sensor that outputs data to your computer through an Arduino microcontroller.
https://www.dfrobot.com/product-1023.html
If you could not use automatic measuring instruments, trapping CO2 could be an answer. CO2 can trapped on KOH solution and become ppt. If you can use conductivity meter, retrieve KOH solution from vial in the falsk and measure conductivity, then you can calculate CO2. Its possible only in small system.
If you can use Gas chromatograph with TCD sensor, just get air with airtight syringe and measure.
Ronnie Concepcion II thank you, this would gave been the best option, but I have almost 20 samples. Also, I don't know if the sensor would align perfectly on the conical flask
Howdy Queency,
A simple but accurate technique is based on Warburg's manometric technique.
See: https://medical-dictionary.thefreedictionary.com/Warburg+manometer
To estimate the amount of CO2 during yeast growth you will need two Warburg manometer vials. One with saturated KOH so that CO2 is taken up and hence only O2 uptake is measured.
To avoid that your respiratory quotient is not equal to 1 (it mostly is), you have to use a second vial without KOH and exactly the same starting conditions as your KOH vial.
You can then subtract the partial pressure measured with the saturated KOH vial from the partial pressure measured with the vial without saturated KOH.
The temperature of both vials has to be exactly the same, preferably immerse both vials in a water bath at a fixed temperature.
Have a good look at Warburg's technique (Nobel Prize winner in Medicine), because other factors (differential solubility of oxygen and carbon dioxide gasses in the manometric indicator liquid) has to be taken into account as well.
Though the principle is simple, the technique is not, but it is cheap and accurate.
You can investigate impacts of temperature, or different yeast substrates and yeast strains on CO2 release and so on.
Give it a try!
Best wishes,
Frank
Kae Kyoung Kwon I have also thought of this method. My culture will be done in a conical flask and I plan to incubate them for some days while monitoring the CO@ production. Do you have a link to a method that can help me construct a small trap that will fit each conical flask. Will a normal CO2 trap used for small brew work
Frank Veroustraete i have a lot of samples, so I am looking for a technique that won't involve a difficult technology to master.
Hi Queency,
I never pretended that science and technology are easy to master. But good scientific results can be obtained only with accurate techniques. That's for sure.
Keep up the good work.
Cheers,
Frank
Using conical flask is enough for test. Actually following article did not describe same method but you can refer it. We'd been use 250 or 500 ml flask and suspend a 20 ml vial by hanging on siliocon stopper. Add 10 ml KOH solution (normality is depend on sample and duration, if high CO2 evolution, high normality is required). Measure conductivity is done after retrieved KOH solution into 15ml tube. You should keep in mind that conductivity is affected by temperature, hence, avoid temperature fluctuation
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