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Stupid question about agar... - (Nov/22/2007 )

Hi all,
I always used bacto agar to make LB agar, but this time, by mistake, I used some agar which is not bacto... It's just "plain" agar, whatever that means...
I noticed my mistake because my LB looked cloudy after autoclaving, almost like if there was bacterial growth (but that made no sense as it has just been sterilized). So I was wondering if I could use this LB : I could not find any information about the purity of the different kinds of agar, but I guess people usually use bacto agar for a reason... Thanks for your help!

-zera-

as long as the medium has gone into the autoclave, it is sterile. I have a medium which is similiar in the sense that in its molten state the medium is cloudy. So don't worry.

I would guess that your LB should be okay. (I too don't know much about agar qualities.) But I believe that agar (no matter the quality) acts as a physical support for the bacteria to grow on. It doesn't really contribute much to e coli's well being.

-perneseblue-

I use "ordinary" agar for preparaing my LB plates regularly. I the medium is a bit cloudy after sterilization - its ok; just swirl the medium well before pouring the plates

-smartsunny-

We also use regular agar in LB here in the lab and it works just fine.

Never tried doing it with bacto or micro-agar though. We just use those for yeast-growing media.

I'm not even sure what the difference is between these types of agar in terms of bacterial/yeast growth...

-AmbrĂ³sio-