Sciencemadness Discussion Board

Substitute for agar

Tiamat - 26-3-2006 at 18:09

Does anyone know what i can use as agar substitute? I live in a country where i cant get agar in greater quantities.THX

chemoleo - 26-3-2006 at 18:12

Try alginate. Not as good but also purely carbohydrates, and Na/Ca. Well you need to make it up in a buffer anyhow.

The_Davster - 26-3-2006 at 18:12

I think homebrew agar can be done with boiled down chicken broth.

http://www.freesciencefairproject.com/biology/bacteria_colon...
http://www.science-projects.com/NAplates.htm
It gives details here.

[Edited on 27-3-2006 by rogue chemist]

Tacho - 27-3-2006 at 06:42

I have never tried any of these for biological use, but here goes my suggetions:

1- Alginate. You can buy that at a dentists supply shop. It's used to make molds. Although it comes with preservatives, I have seen mould grow on old pieces of it, so, if you add the proper nutrients in the mix... It is not transparent though.

2- I have also used another product to make molds that you can find at a dentists supply shop. That is a hard, almost transparent, agar gelatine. The label says it has water, agar, glycerol and preservatives. Here it's called "duplicador". I guess it has even more preservatives than alginate, because it lasts forever with no decomposition. I have left pieces of it on my bench top for weeks. They did shrink a bit due to dryness, but no apparent decomposition. But if you dilute it with nutrient solution, who knows?

3- Those candies sold by weight with shapes like worms or bears. I have a strong impression that those have agar in their formulation. Try to melt them in a nutrient solution. In germany, the name "gummi berchen"(gum bears? sp?) comes to my mind.

4- I have made true gel-like silica gel with sodium silicate and a very dilute acid. I have used hydrochloric, phosphoric, ascorbic and boric acids. I have read somewhere that silica gel is used to grow lithotrophic (sp?) bacteria (bugs that eat rock). Anyway, if you make the gel and then impregnate it with a nutrient solution, you may have a good solid media. Making silica gel is a bit tricky, let me know if you are interested in this route and I will discuss it further.

5- When you cook starch, you end up with a solid semi-transparent media that looks like gelatine. Potato, corn and rice starch are widely available in most places.

6- Most flours generate a solid media after cooked for a while with water. They are quite nutricious too. Grow mould like crazy.

7- Gelatine. Just add as little water as possible. Bacteria and mould atack gelatine, melting it. So does hotter temperatures, but I don't know where you live or what will you grow on it! It may be a good media for plant micropropagation.

Going far out:

8- For fungus? Cheese. Roquefort (blue cheese) and camembert cheese come to my mind as examples of cheese/fungus combination.

9- Casein. Non-fat milk curd. Dissolve it in alkaline solution to make it transparent. I have made it with ammonia.Will anything grow on such alkaline solution? I don't know. But casein glue's worst problem is decomposition by fungus.

10- Still on the fungus path: Plaster of paris. No, really! Gypsum! Impregnate the thing with nutrients, keep it moist and you will have a fungus stravaganza on top of it. Ask anyone who has a damp plaster wall!

I once bought the stuff sold at food stores as agar, but it didn't behave like agar should. Maybe you have more luck.

I am yet to find a reliable agar source.

Good luck.

Edit: If there was an easy, cheap substitute for agar, people would use it more often. Agar is not easy to get and not very cheap. However, one of the above, or a mix of them, may suit your needs.

[Edited on 27-3-2006 by Tacho]

solo - 27-3-2006 at 08:10

Agar is a compound in its own right. It is a polysaccharide found in the cell walls of some red algae and is unusual in containing sulfated galactose monomers. It requires nothing but extraction and purification to become agar, but is sometimes chemically modified into agarose for special applications. Agar added to media simply gels them into a convenient solid form.

Laminaria has various oddball polysaccharides like laminarin (a storage polysaccharide) and alginic acid (from cell walls). They are chemically different from agar and, to my knowledge, not widely used.

Gelatin is not a polysaccharide at all but a mixture of peptides derived from the structural protein collagen. Collagen is the major component of connective tissue, which is why gelatin is derived from animal by-products. As a protein gelatin has considerably different chemical properties from agar.

................source, http://biology.clemson.edu/biolab/agar.html

Tiamat - 28-3-2006 at 14:22

I need agar to grow mushrooms. So little more help, pls.THX

Tiamat - 28-3-2006 at 14:24

is the starch route good for mushrooms?can u give me some recipes

solo - 29-3-2006 at 02:46

I assume you're not tryng to grow regular generic mushrooms, hence only to asume the type you seek are the one's with alkoloids,so here is a small book with the info you seek.............solo

[Edited on 29-3-2006 by solo]

Attachment: Psychedelics--Adam.Gottlieb--Psilocybin.Producers.Guide-1976.pdf (546kB)
This file has been downloaded 1236 times

Tacho - 29-3-2006 at 03:24

I'm not sure if these will suit your needs, Tiamat, but someone else may find them interesting:

11 - Pectin - needs an acid enviroment to gel.

12 - Carboxymethylcellulose (CMC) - does not gel, but thickens any broth.

13 - Gelrite® - gellam gum - substitute for agar. Produced by the bacterium pseudomonas.

prole - 4-4-2006 at 18:00

Tiamat,
The following may or may not help you, as I'm not proposing alternatives to agar, but you may find them helpful anyway. I've learned of and experimented with various low-tech methods of mushroom propagation bipassing sterile technique altogether.

-If you've an abundance of fresh fruitbodies, you may break them up and add them to a few gallons of a molasses/sodium chloride solution and germinate all the spores. This is a spore mass slurry. Then inoculate your favourite appropriate medium, and wait.

-If you've got fresh fruitbodies with stem butts intact (ie, big fuzzy mass of mycelium still attached to the base of the stem), place the butts only on wet corrugated cardboard to propagate the mycelium. It will grow given ample moisture and temperature. This is assuming that your mushroom species is a wood-loving saprophyte. Coprophiles and mycorrhizae may not propagate this way. The mycelium will spread to cover the cardboard 25-50%. You may then break the cardboard up into pieces and inoculate more cardboard. Cardboard seems to favour mycelium and excludes competing molds and other fungi. This works well in your favour. When enough is obtained, a nice fresh pile of wood chips may be inoculated.

-If all's you got is a spore print, you may still scrape them onto some wet cardboard and get them to germinate, and expand the mycelium according to the usual methods. However, if you've paid a hefty price for a print of a 'novel' species, I recommend going the sterile route, at least until you've generated enough for further low-tech experiments.

These methods do not work in a sterile laboratory, and thus must be performed outdoors. Timely watering, proper placement of mushroom beds, and adequate temperatures for fruiting must all come into play for the mycelium to flourish and generate mushrooms. These methods take longer and success is not always guaranteed, but are worthwhile and inexpensive. If you generate enough mycelium, you will get mushrooms, given that you keep the mycelium happy. I've gotten healthy fruitings of Stropharia rugoso-annulata in my backyard using these methods, and this year I plan to expand my mycelial arsenal to include various other species. Last year my wood chip bed was a brilliant snow-white from all the mycelium. For much more detailed info, go to www.fungi.com and check out the books, especially Mycelium Running. This is Paul Stamets' website/store. I've met Paul, he's a great guy and extremely knowledgable on the subject, but Amazon.com's got way cheaper prices on his books. Oh yeah, he sells agar, and ships all over the world.

If you're still after the sterile technique, then nevermind all this. Happy growing and good luck with your mushrooms.

Chucklz - 1-6-2006 at 13:01

Gelatin (120g/L) can be used for some organisms. Others will liquify the gelatin, so you might be out of luck depending on what you are attempting to culture. Agar is available in many supermarkets /asian food stores to make dessert molds that are gelatin free. Also keep a look out for "Vegan" gelatine, which is usually Agar.

Of course you could go real old school, and use autoclaved potatoe slices as a complete solid medium. Not all organisms will grow, but its better than nothing.