4-Stroke
Hazard to Self
Posts: 61
Registered: 20-4-2024
Location: Canada
Member Is Offline
Mood: Often Wrong, Never Unsure
|
|
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...
Ukrainium
|
|
|
Texium
Administrator
Posts: 4748
Registered: 11-1-2014
Location: Salt Lake City
Member Is Offline
Mood: Seeking gainful employment
|
|
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.
|
|
|
Texium
|
Thread Moved
1-12-2024 at 17:31 |
bariumbromate
Hazard to Others
Posts: 105
Registered: 4-2-2025
Location: australia
Member Is Offline
Mood: nitrating
|
|
could you extract methanol (wood alcohol) from it too?
|
|
|
chempyre235
Hazard to Others
Posts: 217
Registered: 21-10-2024
Location: Between Nb and Tc
Member Is Offline
Mood: Quite distracted
|
|
If I remember correctly, methanol is obtained through destructive distillation, not fermentation. Though, there may be some anaerobic microbes that
produce methanol in sufficient amounts.
|
|
|
Sulaiman
International Hazard
Posts: 3947
Registered: 8-2-2015
Member Is Offline
|
|
Sorry, I'm in a negative mood.........
is there an unused excess of sawdust?
could it compete with other crops in litres per acre
or litres per dollar (labour, equipment, pesticides, fertilisers...?)
digestive enzymes seem to me to be a better long term alternative to active heating and cooling.
The potential risk of unintentional methanol (and who knows what else) poisoning due to illicit use of the process is high.
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
davidfetter
Hazard to Self
Posts: 60
Registered: 8-9-2021
Member Is Offline
|
|
Quote: Originally posted by Sulaiman  | | The potential risk of unintentional methanol (and who knows what else) poisoning due to illicit use of the process is high. |
What is your evidentiary basis for this claim?
The reason you find methanol in illicit ethanol isn't some kind of accident or failure of quality control. It's because methanol is cheaper than
ethanol and so is used very intentionally as a bulking agent that's hard for the end user to detect at the point of sale.
|
|
|
Alkoholvergiftung
Hazard to Others
Posts: 238
Registered: 12-7-2018
Member Is Offline
|
|
If you make Wine at home you need it free from pektine containing material (fruit stems)and temperatures low because pektine form Methanol and at high
temperatures your wine containes Methanol too. Bad Wine more Methanol headaches. But if you use it only for fuel production methanols are ok 
|
|
|
bnull
National Hazard
Posts: 995
Registered: 15-1-2024
Location: East Woods
Member Is Offline
Mood: Fecking annoyed
|
|
Have you considered that, if making ethanol from wood was so simple, that there would be persons making moonshine from sawdust and selling the stuff?
Wood is not 100% cellulose, and even if it were, the products of fermentation depend on the conditions to which the yeasts are submitted. You can make
good whiskey from corn or, if you botch it, butyric acid.
[Edited on 3-6-2025 by bnull]
|
|
|
davidfetter
Hazard to Self
Posts: 60
Registered: 8-9-2021
Member Is Offline
|
|
| Quote: Originally posted by bnull |
Have you considered that, if making ethanol from wood was so simple, that there would be persons making moonshine from sawdust and selling the stuff?
Wood is not 100% cellulose, and even if it were, the products of fermentation depend on the conditions to which the yeasts are submitted. You can make
good whiskey from corn or, if you botch it, butyric acid.
[Edited on 3-6-2025 by bnull] |
The original paper was about attempts to make cellulosic ethanol cheaper, i.e. it's for an industrial process intended to scale up well and
down...well, they didn't really consider that as an important thing, so yes, things that have sugars that are easier to access are more suitable than
cellulose at the scales at which illicit production usually operates.
|
|
|
Dr.Bob
International Hazard
Posts: 2918
Registered: 26-1-2011
Location: USA - NC
Member Is Offline
Mood: Mildly disgruntled scientist
|
|
Your saying that 100 g of sawdust can make 25 g of ethanol along with 3 ml of H2SO4, and a lot of energy and water. If you scale that up to 4L or
about a gallon, that would be 4000/25 = 160 times scale and require 480 ml H2SO4, 1600 g of sawdust, and a lot of energy. A half a gallon of H2SO4
alone would cost quite a bit, and bulk ethanol sells for $4 a gallon commercially (before taxes and gasahol rebates). The challenge is that nearly
ANYTHING will ferment to provide dilute ethanol, the cost of that is nearly nothing (waste fruit is often fermented to ethanolic drinks at <
$1/gallon diluted). The cost of distilling it, processing the waste water and chemicals, and handling costs about 80% of the cost of ethanol. So
the issue is dilution, not creation of ethanol. If you could find a way to concentrate it cheaply, that would have a huge impact, which is why some
ethanol companies have looked to solar for distillation energy.
Compare that to crude oil, which sells for about $2/gallon, and provides nearly 90% sellable things from distillation (oil, gas, tar, asphalt, diesel,
etc). It is hard for ANY energy source to beat $2/gallon. Once oil becomes more scarce, which will eventually happen, the shift to other fuels
will be more cost effective.
I still think there is great need to bioengineer some plant that provides seed oil or such at a higher yield than soybeans, rapeseed (Canola oil), or
palm oil, and grows in the US and other moderate climates, and we could make biodiesel very efficiently.
|
|
|
Sulaiman
International Hazard
Posts: 3947
Registered: 8-2-2015
Member Is Offline
|
|
| Quote: Originally posted by davidfetter | | Quote: Originally posted by Sulaiman | | The potential risk of unintentional methanol (and who knows what else) poisoning due to illicit use of the process is high. |
What is your evidentiary basis for this claim?
The reason you find methanol in illicit ethanol isn't some kind of accident or failure of quality control. It's because methanol is cheaper than
ethanol and so is used very intentionally as a bulking agent that's hard for the end user to detect at the point of sale. |
I have no evidence, but I can imagine methanol being a potential contaminant.
Thing is, I don't need proof that it may be a contaminant,
you will have to prove that it is not 
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
chempyre235
Hazard to Others
Posts: 217
Registered: 21-10-2024
Location: Between Nb and Tc
Member Is Offline
Mood: Quite distracted
|
|
| Quote: Originally posted by bnull |
Have you considered that, if making ethanol from wood was so simple, that there would be persons making moonshine from sawdust and selling the stuff?
Wood is not 100% cellulose, and even if it were, the products of fermentation depend on the conditions to which the yeasts are submitted. You can make
good whiskey from corn or, if you botch it, butyric acid. |
Cellulose can be purified from wood by dissolving it in Schweizer's reagent (a strongly basic aqueous solution of sodium hydroxide, copper (II)
hydroxide and ammonia). Acidifying the cellulosic solution will crash out the cellulose. That's how rayon and cellophane were once made.
[Edited on 6/4/2025 by chempyre235]
|
|
|
bnull
National Hazard
Posts: 995
Registered: 15-1-2024
Location: East Woods
Member Is Offline
Mood: Fecking annoyed
|
|
Been there, done that. Not worth bothering if the purpose is to use the cellulose as substrate in alcoholic fermentation. There will be other products
beside ethanol, whether pure cellulose or sawdust is used.
|
|
|
clearly_not_atara
International Hazard
Posts: 2927
Registered: 3-11-2013
Member Is Offline
Mood: Big
|
|
Anyone interested in bioproducts replacing petrochemicals should first start with a good review of resource availability like this one:
https://www.researchgate.net/publication/235205302_Biomass_a...
Otherwise you end up proposing to use things like orange peels as a precursor to gasoline. You need a feedstock before anything else.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
