Glycerol vs. Glucose in bacterial media

Robert Solomon Bioc rgs at
Thu Dec 15 12:15:32 EST 1994

ljlj at (Loren Joseph) writes:
>I would like to know what determines when to use glycerol or
>glucose in media.


Well, my old boss used to advise against using glucose on the basis of
its causing acidification of the cytoplasm during growth (potentially
detrimental to the expressed protein).  So I usually used glycerol at
ca. 30 mM.  But I have not observed much difference in expression/yield
from strains grown at different times with either carbon source. 
Obviously, if using a catabolite promoter (e.g. lac promoter) then
it's best to avoid glucose, but this is not the case for tac promoter,
and I can't see why it should be for lambda pL or pR promoters. 
Ignorance is such bliss.

Rob Solomon
Lost in CyberSpace 

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