Acetic acid vs. citric acid

Thu Nov 14 09:53:22 EST 1996

===== Original Message from ray at sirius.com at 11/14/96 1:43 am
>Hi, all--
>We have a light protein solution that is normally made with a base of .01 M acetic
>acid. The acetic acid supposedly sterilizes the solution, killing all the germs. We want to
>make it with citric acid, at a dilution of 1 gm per 100 gm water. It's just the protein
>and the acid in the solution.
>Here's the question: Will the citric acid kill germs as well as the acetic acid? (Sorry
>about the highly technical language... I hope you know what I mean.)
>We need the answer soon, so if you wouldn't mind answering at your earliest
>convenience, we would appreciate it. Please email as well as post your reply. Thanks
>very much.
===== Comments by TDAWSON at GGPL (Tadd Dawson NCML) at 11/14/96 9:50 am
Hi Katherine;

The acetic acid at 10 mM will generally not be bacteriocidal (killing all 
the germs), but will most likely be bacteriocidal (inhibit the growth of 
some of the bacteria). The acetic acid is most likely be used as a slight 
buffering agent to maintain the protein you are interested in at a specific 
pH (most likely near the pI for the protein). If you need a sterile 
solution, use an autoclave of the media without the protein or filter 
sterilize the solution into a sterile container.

good luck.

Tadd E. Dawson, Ph.D.
Research Animal Scientist
USDA-ARS Beltsville

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