Making Agar for plates at home

[tyso...@gmail.com]

I live in a particularly, let us be kind, small town. My access to
agar-agar and the like from a store is curtailed and due to budgetary
restraints I can't purchase it regularly. However, I know that one can
make agar from potatoes. My mother used to make her own agar from
potatoes and beef stock when she was in med school. However she has
lost all recollection of the method except for, "boil the hell out of
a bunch of potatoes."
I have looked online and haven't found any recipes that do not already
call for having agar. This is quite vexing.
So I beg. I plead. If anyone has a method for making agar at home
please let me know. I would be most appreciative.

[Tito Jankowski]

If you're really in love with the idea of making your own agar, go for it!

If in the end you want to do bio, howabout ordering pre-made agar from Carolina?

http://www.carolina.com/product/0.8-+melt-n-pour+agarose,+400+ml.do?keyword=agarose&sortby=bestMatches

Tito

[Parijata Mackey]

A quick google search brings up potato dextrose agar:

Potato infusion can be made by boiling 300g of sliced (washed but unpeeled) potatoes in water for 30 minutes and then decanting or straining the broth through cheesecloth. Distilled water is added such that the total volume of the suspension is one litre. 20g dextrose is then added and the medium is sterilized by autoclaving at 15psi for 15 minutes.^[2]

To use supply-store-bought agar would not be that expensive, given how little of it is used at a time (you're working with yeast, right? If you're trying to run gels, then you'd be better off with agarose.. I'll write some **footnotes which you can ignore if you're just using it to grow yeast).

Further googling reveals that (Source; this page seems useful for a variety of DIY-agar recipes):

In the early days, only kitchen foods were available for microbiological media. Potato dextrose agar is the most widely used medium for growing fungi and bacteria which attack living plants or decay dead plant matter. This page suggests media that a student can make in his home lab from plant matter such as potato, tomato, flour, cabbage, ssuu. Many species of bacteria and fungi require vitamins or factors from plants.

Here is a link to the Bacteriological Analytical Manual Online, which might not be DIY-ready, but you can use it to compare ingredients, possibly even rewriting DIY-friendly recipes. If you've worked in a lab before, you'll know that labs often have recipe books in which they print out recipes, and write in their own changes; sometimes something done accidentally works better, or sometimes a cheaper ingredient works just as well -- it's useful to have the original recipe printed out, with some DIY-friendly notes written over it. That's what I do, at least, and it works pretty well. Good luck! :-)

**Footnotes on running gels: Here's an old thread on agar purification; here's an old thread on gel-quality agar (agarose); I think the consensus is -- dish out the cash for the "expensive" stuff (~$25-50), then recycle it. Stick with SYBRsafe or something like it, because it gets messy (dangerous) when you try to recycle etbr (please don't do it). Has anyone developed something new, exciting, and relevant that I missed?
 

--
Parijata Mackey
University of Chicago
pari...@uchicago.edu
www.parijata.com

“Seek freedom and become captive of your desires. Seek discipline and find your liberty.” --Frank Herbert

“I am so clever that sometimes I don't understand a single word of what I am saying.” --Oscar Wilde

[Simon Quellen Field]

What you get from potatoes is potato starch, which you can also buy at the store,
or at Amazon.com for $2.49 a pound.

I see no reason why it would not work for culturing bacteria in petri dishes.  Some
bacteria may eat the starch and make it runny, and it may not hold up to being warmed
in an incubator, and the protocols for reproducing other researcher's experiments
will need to be changed somewhat, and it is not clear without experimentation that
potato starch is compatible with all the growth media recipes, but for playing around
at home, I say definitely go for it!  Developing a cheap medium for amateurs and
researchers in poor countries is worth doing.

For something like gel electrophoresis, having high purity gels with uniform
molecular weight aids in getting good resolution.

If the prices at Carolina are too high, you can get Agarose for less than $5:
"http://www.scitoyscatalog.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=Agarose&Category_Code=H".

My latest science fiction novel A Twisted Garden is now available in bookstores.

[kingjacob]

http://www.disknet.com/indiana_biolab/b029.htm looks like they have a recipe for what you're talking about

--
Jacob

[Nathan McCorkle]

On Mon, Oct 12, 2009 at 12:09 PM, tyso...@gmail.com <tyso...@gmail.com> wrote:
>
> I live in a particularly, let us be kind, small town. My access to
> agar-agar and the like from  a store is curtailed and due to budgetary
> restraints I can't purchase it regularly. However, I know that one can
> make agar from potatoes.

No, you can make potato broth from potatoes. You need agar to solidify
it. You can find agar at most asian stores/markets. If you really need
some, I could get some for you and ship it, I think I pay about $1.25
for a few ounces, and you only need 0.5% - 2.0% agar by weight/volume
(so in 100ml of broth, you could add 1 gram of agar to solidify to
1%).

> My mother used to make her own agar from
> potatoes and beef stock when she was in med school. However she has
> lost all recollection of the method except for, "boil the hell out of
> a bunch of potatoes."

That is what you do, then add some dextrose/glucose or corn syrup,
agar powder, then autoclave/pressure cook in mason jars.

> I have looked online and haven't found any recipes that do not already
> call for having agar. This is quite vexing.

Yes, without agar all you can make is broth or sludge which wont solidify.

> So I beg. I plead. If anyone has a method for making agar at home
> please let me know. I would be most appreciative.

Get some cheap agar, lemme know how bad you want it and I can send you
some from the asian market (telephone brand, from thailand I believe)
this week.

> >
>



--
Nathan McCorkle
Rochester Institute of Technology
College of Science, Biotechnology/Bioinformatics

[ben lipkowitz]

On Mon, 12 Oct 2009, tyso...@gmail.com wrote:
>
> I live in a particularly, let us be kind, small town. My access to
> agar-agar and the like from a store is curtailed and due to budgetary
> restraints I can't purchase it regularly. However, I know that one can
> make agar from potatoes.

I just want to point that the reason agar is used for solid bacterial
culture medium is because very few microbes can break it down; it's a
relatively rare sugar. So that means you get nice little blobs popping up
on the surface, instead of a pool of slimy guk embedded in the medium.

Substitutes such as gelatin or potato starch do not have this property.

[J. S. John]

On Mon, Oct 12, 2009 at 12:09 PM, tyso...@gmail.com <tyso...@gmail.com> wrote:
>

> I have looked online and haven't found any recipes that do not already
> call for having agar. This is quite vexing.
> So I beg. I plead. If anyone has a method for making agar at home
> please let me know. I would be most appreciative.

In technical terms, agar( also agar-agar) is "a general name for
polysaccharides extracted from some red algae, is built up of
alternating D- and L-galactopyranose units.[1]"

I think potato starch is composed of amylose chains [2].

I have found some sites for you though:

http://www.shroomery.org/10575/Agar-substitute
-uses rice and used to grow mushrooms

http://www.shroomery.org/search.php?terms=agar
- is a general search for agar from their website

www.umsl.edu/~microbes/pdf/homemademedia.pdf

Hope this helps. I asked about the rice culture in the begining of
DIYbio. Check out the DIYbio archives. I heard Google started to fix
their Groups Search engine.

[1] Algae: Anatomy, Biochemistry, and Biotechnology by Laura Barsanti
and Paolo Gualtieri. Page 270
[2] Potato science and technology By Grażyna Lisińska, Wacław
Leszczyński. Page 282

[Tom Randall]

On Oct 12, 3:58 pm, ben lipkowitz <f...@sdf.lonestar.org> wrote:

> On Mon, 12 Oct 2009, tyson...@gmail.com wrote:
>
> > I live in a particularly, let us be kind, small town. My access to
> > agar-agar and the like from  a store is curtailed and due to budgetary
> > restraints I can't purchase it regularly. However, I know that one can
> > make agar from potatoes.
>

This is a slight tangent, but I recently got some agar-agar from a
local Asian store in order to compare it to standard bacto-agar in LB
(E coli standard media, 0.5% yeast extract, 1% tryptone, 0.5% NaCl) as
a potential substitute. Specifically I want to know if ampicillin
selection and blue/white colorimetric detection with x-gal and IPTG
would work with this stuff. I have tried only one source (Golden Coins
brand) but have been having some problems. First, at concentrations of
up to 4% it does not solidify in petri dishes ever, whereas bacto-agar
will do so at 1.5-2%. Reading the label I noticed the ingredients were
"sucrose, agar-agar", no breakdown given, but likely mostly sucrose,
which explains it's sweet smell. Have gone on to begin washing the
agar-agar in dH2O to reduce the sucrose concentration, that is still
in progress. Has anyone found a brand of agar-agar that works at a
reasonable concentration in solid media? I also need to wash in case I
want to use with some auxotrophic (amino acid and/or vitamin
requiring) fungal strains as who knows what other minor contaminants
may be in this. The presence of sucrose will likely interfere with the
colorimetric x-gal detection in E coli also.

[Meredith L. Patterson]

On Wed, Oct 14, 2009 at 7:36 PM, Tom Randall <tara...@gmail.com> wrote:
> Has anyone found a brand of agar-agar that works at a
> reasonable concentration in solid media?

The agar-agar that I picked up in Japantown in San Francisco gels up
like a champ at 15 grams per liter of liquid medium. It was
straight-up agar, though -- the only sucrose in it was what I added
when I made the nutrient medium.

Sadly, the label has come off it and it is now just a blank silver
bag, so I don't have the name. :-/ I'd just check the ingredients
before buying, next time. Did your Asian grocery store have more than
one brand, or are there other similar stores in the area?

--mlp

[Nathan McCorkle]

I use a Thai brand, called Telephone Brand, 25 grams for $1.50, pure agar-agar

[Tom]

Responding to both below, thanks, the place I looked only had one
brand, I know there are other Asian stores in my area, I just went to
the closest, I will need to check them, and I will READ THE LABEL
before buying this time.

On Oct 14, 2:59 pm, "Meredith L. Patterson" <clonea...@gmail.com>
wrote:

[Jake]

I use bulk agar from my local whole foods co-op. It's used to make
vegetarian jello, but don't get the vegetarian jello, it has
flavorings and sugar in it.

My bulk agar makes good soft agar around 1-1.2% and makes the same gel
strength you'd expect at 2%. So I find it's exactly comparable to the
lab grade stuff at a fraction of the cost.

Haven't tried running gels on it though, just making media.


-Jake

[Mackenzie Cowell]

This is a great thread.

I want to point out that the home tissue culture group (for plant micropropagation) has a similar thread going on right now.  The subject is "Homemade Media Recipe from Carol Update" and has lots of DIY-lore for making agar from a variety of sources.

http://tech.groups.yahoo.com/group/hometissueculture/message/19445

Mac