Hello,

The alginate in the presence of divalent cation mainly calcium may form a gel. The carrageenan may also form a gel

Why?

Hi, so here a little bit of background. I isolated an Algibacter lectus from my plant tissue, however Algibacter lectus is capable to degrade agar, gelatine and starch. So to confirm that he degrades a specific carbon source, which I investigate during my research, I need a media without agar, gelatine or starch.

Interesting, can you grow them in liquid culture with an added carbon source?

BTW, if your bugs can eat gelatin they will probably have no problem with casein.

Acril-amid could be checked, or just liquid mineral medium.

Maybe you can try cellulose? Saw a presentation about this being applied for high-temperature growth conditions, but it might work for you:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2704845/

Hi, Eileen, You can use gerlite or phytagel, but both require presence of divalent cations. You can growth also on a tissue paper, or on liquid medium. I am not sure about casein, they contain a lot of proteins, which itself may have a strong effect. I am not sure about PAA (poly-acril-amid)- it may interact with cations in the medium. Alginate may be a good suggestions. Good luck!

Thank you all for the great input. Algibacter lectus can not degrade Casein. I already cultivating them in liquid with my carbon source and it seems to work, but I would like to confirm, that it is also growing on plates with my carbon source (volatile), but as I said I need to exclude agar, gelantine and starch. So I already know, that it can not degrade casein, so a medium plate with casein would be perfect to show that it can grow on plates but what Casein should I use? I just found the pure protein, which is insoluble in water --> so this does not work and I also want not the really expensive pure protein, I just need Casein. Has anybody experience with Casein as binding agent for plates, which casein to use and how much? Thank you all for the great input. Celluslose and alginate sound good, but I don't know if this bug can degrade these components.

Hi! you can test if your bug can degrade cellulose or alginate that a good start to exclude or not those substracts...

You can dissolve casein ( 2.5%) in 0.1 M NaOH and then change the pH to 7 with HCl, but using the mixer at full power to avoid HCl desnaturation of Casein, below pH 3 the casein will be irreversible desnatured. The comercial casein is more or less all the same.... I use Casein (0.5%) from Merck as a good blocking agent in ELISA assays in polestyrene plates and is diluted after (from 2.5% to 0,5%) in PBS using the method I descrived: the original report about casein as bloking agent in ELISA plates: http://jpkc.jluhp.edu.cn/zwkx/zwbl/improve/tools/Diapops/07-blocking.html

I hope this help.

Hi Eileen Muhs, Please check my US patent. I have used carrageenan as a gelling and solidifying agent instead of agar. Carrageenan has many advantages compared to agar agar. Our group also published paper for agar degrading bacteria, so we have grown agar degrading bacteria in carrageenan plate for culture maintenance.

If you are in the mood for a silly experiment, you can try a preparation of processed and solidified casein - aka cheese.

Hi Eileen, you could maybe try using a polyacrylamide based gel (easy enough to make). Or do a search for other hydrogels.

Hi, Eileen, I am not sure that casein is a best decision, because casein can also subjected to degradation by some kind of bacteria: http://www.microbelibrary.org/library/bacteria/3184-degradation-of-biological-macromolecules-by-bacillus-species

As has been suggested, polaycrialamide may be a decision. All other gelling agents including carrageenan and alginate based on polysaccharides, so, you can not use it for your applications. But you can use liquid medium supplemented with different carbon sources. Therefore, after cultivation for certain period (12 hours, 1 days etc) you can detect behaviour of specific carbon you add to the medium. You can use glucose (but do not autoclave it), sucrose, ramnose, etc. This test may be give you information about carbon source which interact with your bactreia. I hope this will help! Good luck!

depends on what kind of microorganism you want to study

Also, agarose could be applied, usually used for hyper-thermophiles's colonies growth.

It is a good idea to use agarose, however, agarose consist from polysaccharides. In the case if bacteria has a potentials to digest convert polysacharides to sugars, agarose can not be used.

Taras, please give me an

example of bacterium/archaea that grow on agarose (strain and species name).

I found a solution --> Gelrite!

Hi, Eileen, Yes, Gerlite is a good decision, but gerlite is also hetero-polysaccharides (http://zuchtbedarf.de/shop/mikrobiologische-nahrmedien/gelriter.html). If your bacteria can utilize it, you can not use it for growth... Also, please, consider that gerlite may require divalent cations (Ca) for solidification.

Why it should be solid medium? Why not just simple mineral medium?

Dear Eilleen Muhs,

The most inert material for solidifying media is silica. However it is a little bit difficult to prepare. You may find it in Microbiological practice text books (for winogradsky plate silica). I also have found a reference as well: http://pubmedcentralcanada.ca/picrender.cgi?artid=1537444&blobtype=pdf

All the best for your work!

Erzsebet Karaffa

may be you can try out with seaweed extracts

you can try to inoculate your bacteria to BIOLOG, which has Dozens of different carbon source , and get the results automatically

You can use silica gel

If your bacterium hasn't cellulolytic system maybe better to use the wood sawdust.

any agent that is not utilized or broken up by bacteria, not inhibiting bacterial multiplication may be useful

I hope there is no such thing other than Agar agar.

Silica gel in my opinion may be inhibiting bacterial growth

Gellan gum is also used as alternative solidification agent.

You could try using pluronic F-127

http://www.ncbi.nlm.nih.gov/pubmed/19290241

a funny stuff by the way, it a kind of mild detergent, liquid when cold and solid at room temperature, which also allows for making overlays of temperature sensitive organisms.

Eileen--you asked your question many months ago--so hopefully you already have the problem solved. If not--you could use layers of filter paper to provide a cellulosic structure/scaffolding to your medium. Your medium with nutrients/substrate for your microbes could be soaked into the filter paper. Jim White, Rutgers University

Silicagel can be answer to your problem along with casein. In suitable proportions to be tried.