Super Broth

Wed Aug 19 12:55:47 EST 1992

Andrew Cockburn writes...

>I saw an article a few weeks ago in a biotech company's newletter
>touting the advantages of growing plasmids in rich media.  The 
>newletter went the way of all such things, but now I wonder if I
>should have kept it.

>Does anyone have experience using rich media (eg 2x or 3x L broth)
>for growing plasmids in E. coli?  Do the specific vector and host
>matter?  Are the yields high enough to justify switching from L
>broth?  What is your media recipe?  Do you use the same plasmid
>prep as before?

Andrew - 
	For plasmid preps (both large scale and mini) I habitually use
2xYT + 0.2% glucose. 2x YT is (per liter):  16 g Difco Tryptone
                                            10 g Difco Yeast Extract
                                             5 g NaCl

I confess I have never quantitated the difference in yield between this and
standard broth, but eyeball measurement has indicated it to be significant.
Typical yields for 10 ml minipreps are 50-100 ug for pUC-like plasmids. My best
1 liter prep was > 9 mg plasmid. We get different yields from different strains,
but in general we get better yields from "upscale" media. Whether it's worth
it is up to you and probably depends on what your plasmid copy number is. 
Most of us would not use up 9 mg of plasmid in a century, so it may be overkill.
(However, we use pUC for restriction and transformation controls all the time - 
my 9 mg only lasted about 2 years.)

Good luck,
Mike R.

   | Dr. Michael P. Ready                     | READY at UTBC01.CM.UTEXAS.EDU |
   | Clayton Foundation Biochemical Institute | Phone: (512)471-3625       |
   | University of Texas                      | FAX:   (512)471-8696       |
   | Austin, Texas 78737                      |                            |

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