Fusionfire
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Biological propensity for ethanol
Hello all,
I was wondering why biological organisms capable of producing alcohols seem to display convergent evolution towards ethanol, and not other alcohols
(e.g. methanol is simpler)
This includes ethanol from yeast acting on sugars of different molecular structures and from bacteria acting on single carbon sources.
http://en.wikipedia.org/wiki/Ethanol#Fermentation
How are these microorganisms able to selectively produce ethanol despite variations in "raw materials" anyway? If we wanted to produce an alcohol from
a sugar the number of carbons on the backbone will be controlled by where the functional group is. Yet regardless of the sugar source (grapes, cane,
potatoes, juniper berries, corn, barley, rye, etc.) the end product of fermentation with yeast highly favours ethanol to a high proportion, with some
other alcohols.
In terms of consumption, for many animals ethanol is intoxicating but non-lethal (in controlled quantities) whereas methanol is very toxic.
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not_important
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Glycolysis converts glucose into 2 pyruvates plus converting 2 NAD to 2 NADH and 2 ADP to ATP. The pyruvate is then converted to ethanol and CO2.
Before that starches are converted to glucose via hydrolysis, other hexose sugars are converted to glucose.
Going to methanol would entail using C1 pathways, which as less common and generally related to photosynthesis to provide the energy to reduce
oxidised carbon to H3C- or -CH2-
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Fusionfire
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Thanks for the answer.
How can organisms pick which C-C bond to break when they perform glycolysis? Is this on the basis of the physical structure of their enzymes?
Are there any lessons we can learn here on how would one engineer microorganisms to produce copious quantities of industrially significant chemicals?
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Nicodem
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Thread Moved
13-8-2011 at 11:59 |
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