Bumpy agar, is that a problem?

[Moonlight]

I have done experiments using nutrient agar before, but this year something quite unusual happened.. after I melted the agar to pour into the petri plates, I found lumps in it. Therefore some of the plates are now bumpy. I don't have time to order any new materials, so my question is: Will the bumpy agar be a problem? Do I need to treat them differently than how I would use and treat a smoother plate of agar? If you have any other suggestions please let me know. Thank you very much for your help.

[James]

Hi Moonlight,

You might have gotten bumpy agar because of air bubbles. Sometimes, when agar is poured too quickly, bubbles can form and if untouched, will dry as is. Additionally, it may be that your agar was not fully dissolved in liquid. Consequently, the choppy and rough consistency of your agar may contribute to "bumpy" stuff. Nonetheless, rough agar is the same as smooth agar in composition. Depending on what you are trying to do, there may be obstacles to using bumpy agar. I don't know how your agar looks; but, you should note that when you spread our organism of interest on the agar, take extra precaution to spread the organism "soup" all over the plate...not just where the surface is smooth. You don't want your organism of interest crowded.

Hope that helps,

James

[surekhamuralidharan]

Moonlight,

The lumps in your Agar may also be due to letting the agar sit out too long, if you had allowed it to cool too long before pouring. This would have cuased it to start hardening in clumps before you even poured. However, in either case, I don't think there sould be any real problem with your experiment. (Just in case, mention this as an error in your writeup)

Surekha.