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Author: Subject: Bio-stoichiometry & baker's yeast question
scientician
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[*] posted on 15-12-2010 at 01:41
Bio-stoichiometry & baker's yeast question


It has recently been brought to my attention that baker's yeast can be made to produce alcohols from nearly any carbonyl via an enzymatic reduction. Not only that, but the very same organism can also reduce alcohols to their corresponding aldehydes and ketones; one need only change the conditions from respiration to fermentation. Imagine my unchained glee.

However, I'm vexed at how the stoichiometry would work in such a situation. How would one predict when the desired reaction has run it's course? What ratios of substrate to yeast to sugar need to be used? Also, is there any hope of avoiding side reactions? I have a hard time trusting an enzyme which will oxidize or reduce nearly any substrate.

Finally, assuming that a given molecule has two ketones, one sterically hindered and the other much less so, is it reasonable to expect selective reduction of the sterically hindered ketone despite the promiscuity of the enzymes involved?

By the way; Hi, my name is scientician and I'm a first year grad student studying medicinal chemistry in the Seattle area. Please don't insult me too viciously; I'm extremely sensitive and prone to petty acts of self harm (such as plucking out my arms hairs one at a time,) when upset.
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[*] posted on 15-12-2010 at 11:53


Quote:
Not only that, but the very same organism can also reduce alcohols to their corresponding aldehydes and ketones


Oxidize, you mean.
I wouldn't expect neat stoichiometry, rather I would expect the appropriate conditions and ratios to be determined experimentally.

Quote:
Also, is there any hope of avoiding side reactions?


No. Pretty sure that any attempt to synthesize pure chemicals via fermentation is going to have a substantial workup at the end to get rid of all of the unwanted crap. Even ethanol from sugar needs flocculation, filtration, cleaning with activated carbon and distillation.

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