LB media chemical composition

Scott Coutts scott.coutts at
Thu Feb 12 21:03:00 EST 2004

Marcin Imielinski wrote:

> Hello,
> I have a pretty basic question for which I have had difficulty finding
> the answer to ...
> What is the chemical composition of LB media?  The product sheets
> generally list the "ingredients" as tryptone and yeast extract, and some
> list the composition in terms of amino acids and electrolytes.  But it
> appears that given its messy origins this LB should be quite a bit more
> rich with metabolites.  For example does LB contain nitrogenous bases or
> nucleotides?  What carbohydrates are known to be present?

Well, you'd have to look for the chemical analysis of the individual 
'ingredients'. As you say, in the lab, it's made up from trypton, yest 
extract, salt and water. I assume you know what yeast extract and 
trypton actually are? You're not going to get a complete and 
comprehensive chemical analysis because these ingredients are too 
complex. It's not a chemically defined medium!


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