Suggestions needed: Adjusting a DL39-based auxotroph to minimal media.

John Tomaszewski tomasz at
Fri Jul 10 17:09:00 EST 1998

Hi all,
	In the past I've had no trouble getting M15 and BL21 strains of 
E.coli to grow in minimal media (M9 supplemented with vitamins and 
minerals, or another MOPS-based media) but I'm having a dickens of a time 
with this DL39-derived Asp auxotroph to come around.
	It grows very well in LB but, in M9 containing 100-400mg/L Asp, the 
highest OD600 I've seen was 0.8 and it's usually 0.4-0.5.  I've tried 
both, taking aliquots of growing cultures and adding to new media, and 
centrifuging growing cultures (5min, 4000RPM) and resuspending the 
pellets in fresh media, to no avail.  Thus far all has been done either 
as 100ml cultures in 500ml Erl. flasks or 250ml cultures in 1L Erl. 
flasks, 37 deg. C, 300RPM.  I'm trying to get them up above one before 
using them to start a 5L culture in the fermenter.
	Any suggestions or critiques would be greatly appreciated.


John T.

**  **  ** ** * **            DEPARTMENT OF CHEMISTRY             **
**  **  ** ** * **        tomasz at      **
**  **  ** ** * **                (206) 616-2993                  **
**   *****  *****                JOHN TOMASZEWSKI                 ** 

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