LB vs. TB?

Michael G. Kurilla mgk2r at Virginia.EDU
Wed Nov 17 17:33:11 EST 1993


medtjm at bimcore.emory.edu  writes:
> In article bloksber at thomashaw-at.css.msu.edu, bloksber at pilot.msu.edu  (Leonard N. Bloksberg) writes:
> > I have heard claims of doubling plasmid yields by growing bugs up in TB 
> > rather than LB.  Does anyone have any experience to support or debunk this
> > notion?  Since TB is more trouble to make up, and costs a lot more, is it 
> > worth it?  Media recipes follow.  Thanks.
> > ..
> > 	LB  (just for direct comparison)
> > ..
> > 					      Per Liter
> > Tryptone (Casein digest)			10 gm
> > Yeast Extract					 5 gm
> > NaCl						10 gm
> > 	pH				7.4
> > ..
> > ------------------------------------------------------------
> > ..
> > 	Part A (900ml)			      Per Liter
> > Tryptone (Casein digest)			12 gm
> > Yeast Extract					24 gm
> > Glycerol					 4 ml
> > ..
> > 	Part B (add 100 ml to part A)	      Per Liter
> > KH2PO4	(170mM)					23.14 gm
> > K2HPO4 	(720mM)				       125.41 gm
> > ..
> > 	Mix 900ml A plus 100ml B after autoclaving.
> > ..
> > ..
> > ..
> 
> 
> 
> My lab started playing with TB several months ago.  We now
> use it for large scale plasmid preps, but use 2XYT for minipreps.
> We no longer use LB for anything.
> TB is too rich for minipreps by alkaline lysis, the DNA from TB mini-
> cultures is contaminated with inhibitors of many restriction
> enzymes...I guess complex carbohydrates but am not really sure. 
> 

We use TB for minipreps all the time.  We grow 0.5 ml minipreps
in 1.5 ml microfuge tubes.  The limit on aeration may slow the
growth, but the 0.5 ml grows TO about the same level as 1.5 ml
of LB with two differences.  Less time is needed, set them up
in the morning and harvest by mid afternoon (5 - 6 hours), and
fewer tubes to label.  We grow and perform DNA isolation all in
the same tube.  So far, we have not found an RE that won't cut.

> Yes, you can get phenomenal growth and yield in TB compared to LB.
> For large scale preps, we get better than 4X what we were getting in
> LB, wheras LB gave maybe 1 mg plasmid/liter, TB is giving 4-5 mg/l.
> 
> My guess is the big factor is the glycerol in TB as carbon source is 
> what makes the T in TB.
> 

I wonder if the buffering capacity along with K might be
helpful.

> We started getting poor yields from LB (using Sigma premade), so made
> the switch.  You can buy premixed TB media now from Gibco.
> 
> So TB for large scale cultures only gets a high rec from my group.
> 
> TJM
> 
> 

Mike Kurilla
mgk2r at virginai.edu



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