by Christoph
Say, you are a student in a molecular genetics lab course or a more advanced cloning expert, you will inevitably have to deal with E. coli. And to make E. coli bacteria grow quickly, standard protocols almost always suggest using LB medium as a "rich medium". You follow the protocol… and then you run into trouble, so you go troubleshooting. Or you are just simply curious why everyone uses LB Medium.
That is what we at STC imagine when we find – occasionally, there's no constant "tracking" – that one of our ~1950 pages has been continually googled for many years. It's this one: The Limitations of LB Medium by Hiroshi Nikaido, posted on November 09, 2009. There, Nikaidosan says:
Figure 1. Single colony streak of E. coli O104:H4 on LB plate. Photo by akseabird, Flickr (CC BY-NC 2.0
"While this may appear a tasty dish for many bacteria of research interest, it is an inappropriate choice for physiological studies wherein reproducibility is required. Since only bacterial cultures in balanced growth (achieved by sufficient time in exponential growth) have a reproducible average cell size and chemical composition, none of the components of liquid media should become exhausted during growth of the culture. Is this the case with LB broth? To answer this question, we must know what limits bacterial growth in LB broth."
It is a fine reward for us that STC is a sought-after resource. Nikaidosan's piece even made it into the reference list as #64 of a paper published in the Journal of Bacteriology. We will not do more today than provide the link to this page again: The Limitations of LB Medium by Hiroshi Nikaido. If the link to Nikaidosan's blog entry is not convenient for you, you can also download it here as a PDF.
Nikaidosan had mentioned two media in his piece, but did not provide links to them, so we are providing them here: Muller-Hinton Medium and Fred Neidhardt's MOPS Minimal Medium. In his last sentence he says: "I must confess that I have been guilty of committing this sin many times in my career." Growing E. coli in LB medium is the "sin", and all of us at STC freely admit that we are also guilty of this sin, many times.
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