LB Broth Alternative

Discussion in 'Supporting Biology' started by Omni, Mar 3, 2020.

  1. Our students are carrying out a PAG that requires LB Broth - but it is going to cost over £50 to buy the broth with postage and packaging - does anyone know an alternative to LB Broth. Thanks
     
  2. Make your own if you have the ingredients
    H2O 950 mL
    Tryptone 10 g
    NaCl 10 g
    Yeast extract 5 g
    Combine the reagents and shake until the solutes have dissolved. Adjust the pH to 7.0 with 5 N NaOH (~0.2 mL). Adjust the final volume of the solution to 1 L with H2O. Sterilize by autoclaving for 20 min at 15 psi (1.05 kg/cm2) on liquid cycle.
    For solid medium, add 28g Agar
     
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  3. I just used the usual nutrient broth for this PAG that I usually use for subculturing. Worked fine.
     
    Last edited: Mar 4, 2020
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  4. Few schools will have the Tryptone due to its expense. It sounds to me that you are attempting to grow the bacteria found in live yoghurt.. I have succeded in growing them on Nutrient agar plates supplemented with 1% glucose and 1% marmite (yeast extract). Indeed a couple of weeks ago when we did transformation of E. coli with the pGlo plasmid I tried growing the un transformed E. coli and transformed E. coli on Nutrient agar instead of the LB agar and they grew incredibly well.
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  5. I would just grow them in sterilized milk.
     
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  6. A nice idea Paul, but the bacteria (L. casei) are particularly fussy and prefer a richer medium.

    upload_2020-3-4_12-10-16.png
     
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  7. yakult will disagree with you.

    can't be that fussy
     
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  8. Yakult is heavily enriched with glucose and fructose.
     
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  9. And the Gut Paul.:)
     
  10. We carried out this PAG a couple of weeks ago and chose to use nutrient broth instead of LB. We got the desired results from this and couldn't see why they were specifying LB. I think they just like to throw in the occasional curveball, just because they can.
     
  11. Not a curveball as such Lynda - it's just that some bacteria prefer this medium for good growth whereas if you grow the same bacteria on bog standard Nutrient agar you get very poor growth.:)