[sisara]

hi all
I'm trying to convert glucose to ethanol via different conditions such as follows:
1- 2gr D-glucose- 1 gr yeast (Saccharomyces cerevisiae) + 50 ml distilled water
2- 2 gr D-glucose + 1 gr yeast+ 1 gr k₂HPO₄+ 1 gr yeast extract granulated+ 50 ml distilled water
 the pH was about 5 and they were on a heater which temperature was about 50 ^oC, and were held in a flask (100 ml) which mouth was closed with a balloon, and the reaction was kept about 24 hours. also the yeast was new but they didn't produce ethanol, (just the first one about 3% ) I don't know what's the problem. and how can i solve it, also one of important things is the reaction produce some how a large amount of gas in initial hours then the volume of balloon is decreased I don't know it is related to CO₂ dissolution in the reaction mixture or it is penetrated from the balloon.
I would be grateful if you help me.
thanks in advance for your help

[Borek]

they were on a heater which temperature was about 50 ^oC

Sounds high to me.

[rolnor]

Agree, why heat it?

[sisara]

Agree, why heat it?

because I saw in the chat gpt that the optimized  temperature is between 30 to 35^oC and because at this season our temperature is about 20 or less I put them on a heater.

[Borek]

the optimized  temperature is between 30 to 35^oC

Yes, but that's far from 50°C.

[Babcock_Hall]

https://onlinelibrary.wiley.com/doi/abs/10.1002/j.2050-0416.1977.tb06813.x
"The maximum temperatures for growth (Tmax) for all strains of S. cerevisiae examined were in the range 37.5°C-39.8°C and the optimum temperatures for the most rapid initial growth (Topt) were in the range 30.0°C-35.0°C."