Hilski
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Yeast extract
I've been playing around with yeast some lately, just trying to see what I can learn. I've been growing some ordinary bakers yeast in corn syrup
and/or molasses and water, and I would like to make some yeast extract out of it for use in further yeast experiments.
As I understand it, the basic process for making yeast extract is to add enough water to a volume of yeast to make a slurry. This slurry is then
heated at 50C for 12 - 24 hours. The husks and other solids are then filtered out of the remaining liquid, which contains the yeast extract.
Does this sound like a practical method for making yeast extract? Also, how much of this yeast extract should be used for a fermentation of a given
size? I am referring to biosynthesis type projects with fermentations that last only a day or so, and use molasses or corn syrup with water and added
thiamine for media.
Thanks
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Organikum
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Just search for "yeast autolysis". If you cannot find the needed information (what would surprise me), tell and I look it up in my notes.
It sounds basically right to me, how to make Vegemite is no secret at all. You will get a slimy mess, filtration through a cloth or celite is advised,
it will clog any other filter (a centrifuge or a filter press would be ideal though). You will also have to add a lot more water to make the mess
filtrable.
/ORG
PS: Thiamine is a double edged sword. Too much will ruin your yields for sure.
[Edited on 11-12-2006 by Organikum]
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roamingnome
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http://jb.asm.org/cgi/reprint/132/2/738.pdf
your yeast extract needs may be differnt then mine
i want to filter actively growing yeast cells and this paper suggests they are
approx. 71.5 micrometers cubed if not nitrogen starved, which makes them smaller but more numerous....
what type of filters for this pore size?
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chemrox
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This may be off-thread a bit but have you guys worked with centrifuges? Big enough one cost too much buit there is such a thing as a dairy
centrifuge. Many of these are hand operated and have two or four cylinders. I was thinking of including benzal in our yeast/fermentation
experiments. Acetone and pentanol are on the drawing board too..do we need to worry about separation of the yeast stuff?
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roamingnome
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to answer my own question i think a 1 micron pore size is good. they make nylon mesh that size but its cost like 50 bucks....
ive been toying around with the idea of building a basic centrifuge, maybye buy a rotor and just spin it with a motor... or somthing....
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