bereal511
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Butyric acid from sucrose
For the past month, I've been trying to collect butyric acid as a byproduct of the fermentation of sugar. I first tried to collect the whole
collection of bacteria that can ferment sugar to butyric acid by innoculating a chunk of cheese with soil and allowing it to stand until the cheese
began to give off the characteristic smell of butyric acid, vomit . I used this technique because I had read on Wiki that in the past, butyric acid
was produced "...by the fermentation of sugar or starch, brought about by the addition of putrefying cheese, with calcium carbonate added to
neutralize the acids." So then I prepared a gallon of growth solution containing 80 grams of sugar, 6 grams ammonium sulfate, 5 grams of sodium
bicarbonate, 1 gram of magnesium sulfate, and 2 grams of sodium chloride, extrapolated from data from this experimental procedure:
http://www.zju.edu.cn/jzus/2005/B0511/B051105.pdf
I then added the putrified cheese and 100 grams of calcium carbonate in excess to neutralize the butyric acid that would form. The container was
sealed off with a rubber stopper and a glass U-tube jetting out of the stopper hole to release outlet gases. Each day, I added 20 grams of sugar and
15 grams of calcium carbonate.
Yes, I'm aware that butter can be hydrolyzed to form butyrate salts, but I just wanted to see if this method was a possible way to generate large
amounts of butyric acid without buying pounds of butter and sodium hydroxide. Plus it's more fun.
So after the initial 3 or 4 days, the mixture bubbled with the indicative fermentation and neutralization gases. And the smell of butyric acid did
indeed grow a bit stronger each day. But after about a week in, the bacteria stopped fermenting and nothing happened for about another week.
Then about 3 days ago, the solution began to bubble vigorously out of random. I currently can't smell anything because I have a heavy cold, so I
can't sense if there's any production of butyric acid and I probably won't be able to for about another week.
And so I have two questions. One, is it possible that the butyric acid producing bacteria laid dormant or was dying because of some competing
bacteria and now it is beginning to take over, or did some contamination of yeast get in and start to produce ethanol? And two, is there a test
solution that can be prepared to determine if the contents of solution is indeed calcium butyrate, or if the new products of the second fermentation
is ethanol?
[Edited on 15-2-2007 by bereal511]
As an adolescent I aspired to lasting fame, I craved factual certainty, and I thirsted for a meaningful vision of human life -- so I became a
scientist. This is like becoming an archbishop so you can meet girls.
-- Matt Cartmill
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not_important
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I believe there's another thread on this already. But in quick response, the normal route for what you are trying was to ferment the sugar to calcium
lactate, then add the cheese to start the fermentation of lactate to butyrate.
One way to see what you have is to take 20 - 50 ml, add a little more CaCO3 to make sure there's no free acid, and distill it. If you get much coming
over around the boiling point of the etOH-H2O azeotrope, then you know you've got ethanol fermentation. After distilling half to 2/3 the liquid, cool
it and add HCl or H2SO4; you should be able to smell free butyric acid and/or co-distill it with some of the water.
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Sauron
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I believe there are enzymes available to convert sugar to butanol, certainly to pentanols (amylases) and getting from butanol to butyric acid is
hardly a challenge.
These processes tend so smell to high heaven but you know that.
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bereal511
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Hmm, indeed there is another thread on butyric acid. Though only a snippet covers the fermentation process.
http://www.sciencemadness.org/talk/viewthread.php?tid=6401#p...
As an adolescent I aspired to lasting fame, I craved factual certainty, and I thirsted for a meaningful vision of human life -- so I became a
scientist. This is like becoming an archbishop so you can meet girls.
-- Matt Cartmill
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