# DIY yeast co2 production: aerobically vs anaerobically



## shev (Jan 18, 2005)

aerobiosis vs. anarobiosis, we went through this in biology a while ago, maybe i should ask my teacher
Glucose + Oxygen —> Carbon dioxide + Water + Energy
Glucose —> Carbon dioxide + Alcohol + Energy

with oxygen it doesnt make alcohol, and alcohol kills the yeast. so yeast uses oxygen and the energy in glucose to live, and multiplys, then needs other nutrients like nitrogen.

without oxygen it still uses the energy in glucose to live, but does it multiply? also without oxygen it makes alcohol in fermentation, and alchol is still holding alot of the energy, so with oxygen alcohol isnt produced, and so it has more energy to do other stuff? does it multiply slower without oxygen?
so would with oxygen make more co2, or kill less of the yeast without the alcohol? would i have to add nitrogen or something? (and isnt nitrogen in fertilizers, but is hard to get nitrogen because of people making bombs with it?)
so which is better?

I have a water pump thing that has areas to put 2 tubes, one that sucks in water, the other that sucks in air, they combine and shoot out another hole.









I know im an amazing artist. is there some obvious flaw im am not thinking of?

the tube coming from the pump into the seperator bottle is larger than both of the smaller tubes coming fom the other co2 generating bottles, so it'd make a vaccuum, but would that gradually destroy the motor in the pump?


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## Damon (Jan 18, 2005)

I'll take a shot at this...................
It would wear down the motor but not anytime soon. It will add noise to your powerhead and the impeller churns up the bubbles.
I think I see a problem with your theory. Yeast the reiceve a constant supply of O2 would deffinitely live longer. The problem is CO2 loss. IF the CO2 bottle isn't sealed, you will not be recieving 100% co2 but more O2 than CO2. Adding O2 into your tank will in fact reduce your CO2 uptake. A setup for your system to work would cost more than a typical DIY unit should. Probably be cheaper to buy a 5lb CO2 bottle and use a DIY reactor (less than $140.00). And the tank would deffinitely last longer. I like the idea though.


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## shev (Jan 18, 2005)

thanks simpte i never thought of that. hmmmmmmm Co2 dissolves under high pressure and cooler temperatures but i doubt either could be worked into a diy system.


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## Damon (Jan 18, 2005)

I'd agree with you. Although it could be done, the cost is very prohibitive.


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## brandonschnupp (Jan 19, 2005)

hmm it really isnt bio its more Chemistry, and also i dont know how this would work..


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## shev (Jan 18, 2005)

no, it's biology. i guess it'd also be chemistry but reactions are because of a living organism. http://www.cofalec.com/scie1e.htm is a great site.





> hmm it really isnt bio its more Chemistry, and also i dont know how this would work..


pretty simple, in regular diy systems all bottles are sealed except for one tube that allows the co2 that the yeast produced to leave and go into the aquarium, but oxygen isnt coming back up the tube, so they yeast go through fermentation, which means they still use the gluccose even if there isnt oxygen, and they produce alcohol. same thing happens with your muscles, there is anaroebic and aerobic activities. aerobic would be like jogging where you breathe alot, and oxygen can get to your muscles. anarobic would be like pushups, after using all the atps and oxygen in the muscels very quickly, so they have to use fermentation, that prodces lactic acid, which is why muscles are sore after working out too much.

but with the system above, oxygen would be allowed to come through the tubes coming out of the bottles, but co2 wouldnt be able to escape out of them. and since there is oxygen the yeast could live longer and reproduce more. the co2 and water would meet and be combined in the pump, and get pushed out into the water. but there would be a lot more o2 than co2 coming from the bottles. and as simpte said, that would screw it up, and the co2 wouldnt be absorbed into the water.



> Probably be cheaper to buy a 5lb CO2 bottle and use a DIY reactor (less than $140.00)


 i have a co2 cannister for a paintball gun, im pretty sure its co2 and not compressed o2. but wouldnt i need a co2 regulaor? and those things can be expensive.

ive been on ebay looking at stuff.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=46310&item=4354941773&rd=1
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=3212&item=4353928633&rd=1
how does the first one work?



> Adding O2 into your tank will in fact reduce your CO2 uptake


why? i know it does, but why does it? is it because of surface agitation releasing the co2? and would a good diffuser fix the problem? more co2 in an aquarium with plants puts more oxygen into the water than without co2 and extra CO2 does not displace any oxygen, and vise versa.


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## Damon (Jan 18, 2005)

The problem comes because you cant keep the CO2 seperate from the O2. Because CO2 is being produce in a confined space, there is too much pressure. That alone will push all gas (lighter gasses will move more) through the tube. Adding a carbon element to O2 will cause it to be heavier thus moving less. You will push more O2 than CO2 through the tube and in theory, outgas yourself before you start. This defeats the purpose of adding CO2 into the tank.


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