Autoclaving cell media - Necessary to autoclave sub-solutions? (Jun/20/2007 )

Hello,

I am planning on making the 100x and 1000x solutions identified in BG-11 recipe 2 at the bottom of the following page:

http://139.57.180.167/wiki/index.php/Growing_Bugs

That recipe seems to say to autoclave the final 1x solution, which makes sense. What I am wondering is if I should also autoclave the 100x and 1000x stock solutions that are used to make up that final 1x solution. I am thinking that if I don't autoclave them then some bacterial contamination may change the composition of the stock solution, but also that if it's not necessary to autoclave these stock solutions then I should not so as to be more certain about the final concentration. What would you recommend as the best practice?

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best practise would be to filter sterile all the solutions. This is the safe thing to do.

The driving without a seatbelt option:
-from my experience, if you prepare your media using miliQ water and sterile bottles, only the carbon containing solutions require sterilisation. In this case the 1000X Ferric Ammonium Citrate. The other mineral solution just don't contain enough food stuff for bugs to grow well.

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Always filter sterilise...this means using a 0.22uM filter. Autoclaving is not an option and I have never worked in a lab that would do that.

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As a follow-up, why don't you autoclave the solution? Is the concern that there would be trace metal contamination from the autoclave?

If so, then is it even ok to autoclave the dry bottle which will later hold the filter-sterilized media?

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Why wouldn't you autoclave the media?? I have never worked with cyanobacteria (is that what BG-11 is for??), is it something specific to do with this media or bacteria???
We always autoclave our bacterial agar and media and have never had a problem. All of the labs in my microbiology department do the same.....

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