I usually don't but since I'm about to use zeocin, I thought I'll make it "by the rules". However, because I do not remember what value it should be titrated to, I checked the internet and found the article @ Wiki, which is pretty strict about the uselessness of pH adjustment of LB. I know that NaOH does not buffer, but I thought the organic compounds in tryptone or yeast extract might have buffering capacity. Not to say that if you increase the pH, it will take longer for the bacteria to lower it too much.
So what's your opinion?
http://en.wikipedia.org/wiki/Lysogeny_broth#Adjusting_the_pH
I always make sure it is pH 7.4. Like Monzur, I was also using NaOH (1M). However, my colleagues said I didn't really need to bother with it. I still wanted to keep it correct and I was adding antibiotics later on to some of the assays, so it was useful to be on the spot with the correct pH.
I have never adjusted the pH of any bacterial growth media, and have added antibiotics to them all.
But I only use the bacteria to over express recombinant proteins. Note some bacterial media like Terrific Broth include a phosphate buffering system.
For our gene transcription studies we add A GOOD buffer - like MOPS and adjust to pH 7.4 to avoid acid effects.
Of course from pH depend not only bacteria multiplication, as well for example a titre of phages. it's reason why important know and controling value of pH of LB nutrition.
LB medium does not need titration. You may need to adjust the pH according to the standard.
You want to say that using "titrate LB" means adjust the pH. In our lab, we have controlled the pH and adjusted the pH of LB medium. Also medium content changes during the bacterial growth.
These ready to use media are quite well prepared and maintain a strict range of pH when prepared. I have taken care to check the final pH to make sure that everything goes well. I would rather keep a check on the pH of DW/other water while preparing the media. Sometimes, we have used MOPS or similar buffers.
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