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Author: Subject: Ethanol from Wood
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[*] posted on 1-12-2024 at 16:30
Ethanol from Wood


Cellulosic ethanol has been produced for over a hundred years, but has never become economically viable. The main issue was just the amount of equipment and work needed, as well as the recovery/disposal of the acid. But anyways, here is a procedure I found that seems pretty cheap, easy, high-yielding, and just objectively easy to do. I wonder why it hasn't been implemented industrially.
Quote:
100g of fine sawdust was added to 100ml conical flask and 100ml of 0.4M H2SO4 was added
to it. The pH of the mixture was 3.1, thus, 0.01M Ca(OH)2 was prepared and added in drops
until pH of 4.61 was attained. The mixture was put in an autoclave and was subjected to a
temperature of 120C for 10minutes. The mixture was then removed but because the
temperature was too high for enzymes to be added, so it was cooled in a refrigerator until a
temperature of about 30C was attained. The sugar content was tested for to be 24.7g. After
which the 2.5g of cellulose was added and Saccharomyces cerevisiae was added. The mixture
was kept in a shaker incubator at 150rpm for 48hours – 72 hours at 30C to allow it to
ferment completely. On a four hourly basis, the mixture was tested for sugar content to
determine rate of fermentation with time and the time required. 100ml of sample was distilled
in a distillation bath and 6.3ml of ethanol was distilled at 78C.


100g sawdust into 25ml of ethanol? Seems pretty impressive!
Very little acid needed (it is 0.4M, so that's under 3ml of concentrated sulfuric acid needed for the entire operation).
No expensive equipment needed (an autoclave? Sounds like a pressure cooker to me! And I presume that the incubator is also optional).

So, what do you think? It should be easy to try this at home, right? Doesn't it seem to you like this entire procedure is too good to be true? But will it still work?

Thanks.

The procedure: https://www.theseus.fi/bitstream/handle/10024/42578/Otulugbu...




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[*] posted on 1-12-2024 at 17:31


Why hasn’t it been implemented industrially? Government agricultural subsidies. In the US, corn is heavily subsidized to incentivize farmers to grow more and keep it dirt cheap. Brazil does the same with sugarcane.

As far as the viability of the procedure for a home lab, you can only cut so many corners. Pressure cooker should be fine, but the incubator may be harder to avoid than you think. Successful fermentation requires good temperature control. You’ll need some way to keep the temperature at a steady 30 °C, or you’ll risk killing your yeast or having it produce very slowly. The shaking is also important to ensure the yeast finds all the fermentables quickly. Not shaking will cause it to take significantly longer, and your ultimate yield may be lower. Gentle magnetic stirring might work instead, but I’d be concerned about killing yeast through physical abrasion with the stir bar on the glass. I’m not a biosynthesis expert by any means though, so take this advice with a grain of salt.




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