Lactose intolerant E. coli
Name: Carolyn M McPherson
I am a teacher seeking information for one of my students who is
interested in researching lactose intolerance. She wishes to test bacteria
(E. coli have been suggested) for intolerance. Is there a procedure for doing this?
Do you have other suggestions or advice?
This student is a high school sophomore.
Yes there is a way to find E coli that can't metabolize lactose.
In fact, it's one of the most commonly used methods in
molecular biology. A colorless chemical (called X-Gal for short)
turns blue if the bacterium can metabolize lactose, and stays clear
otherwise. SO, if we have X-gal in the agar plate, and streak out the
bacteria, the WHITE colonies are lactose-intolerant!
I don't know for sure, but I will bet that most of the usual supply
houses can provide a kit for this purpose.
Steve J Triezenberg
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Update: June 2012