Is there a cheaper alternative to IPTG?

Zophonias O. Jonsson zjons at
Fri Dec 9 10:55:10 EST 1994

In article <tan-0812941554100001 at>, tan at (Song
Tan) wrote:

> Someone in our lab tried unsuccessfully to use lactose instead of IPTG for
> induction a while ago and decided the problem was pH changes as the
> lactose was hydrolyzed by the cells.  IPTG doesn't suffer from this
> problem because it is nonhydrolyzable, of course.  
> Still, I've love to hear if others have been successful in replacing IPTG
> with lactose.
  I had the same experience when I tried this.  My cultures went sour
(literally) when the bacteria started to ferment the lactose.  I did not
pursue this, but I guess you have to use a well buffered medium such as TB
or titrate the culture with Sodium Carbonate (or whatever) after adding the
Lactose.  I'm sure someone will know the trick and share it with us.


Zophonias O. Jonsson

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