# how to make agar?

## Recommended Posts

huahe    10

hello guys!

Biologist often use agar to plant things, and I would like to know how to make agar......

Thanks for any help in advance.

##### Share on other sites
Skye    143

Buy it, it's like gelatin, but it's made from seaweed and it's firmer than gelatin. You can buy agar ready-made in petri dishes from science suppliers, or from somewhere like ebay. These will have the agar and some nutrients to help the bacteria grow. Make sure you get the right nutrients for the type of bacteria you want to grow. You can also buy agar powder and make it up yourself. Something like this:

http://www.science-projects.com/NAplates.htm

##### Share on other sites
YT2095    591

ordinary cooking gelatine works great too, be sure to boil the mixture for a good 5 minutes before using it though (it helps elliminate most bio contaminants).

for plants as mentioned above, youll need the correct nutrients as what will work great bacterial cultures (I use a little Chicken OXO) will not work for plants, maybe a pinch of hormone rooting powder added to the mix will help, thats something youll have to study up on. Cookie may be able to help when shes on

##### Share on other sites

Well, if you just want to plant seeds and move them to soil once they've sprouted, then the key thing is moisture and most plain agar plates should work fine so long as they are moist. (but then again, so will a moist paper towel) If, however, you want to regenerate whole plants from plant parts, or you want to do long-term plant tissue culture then you're going to need several other micro and macronutrients, and my advice to you at that point would be to buy it prepared from a science supplier because that will probably work out cheaper for you than having to buy every individual component. Unlike bacteria, as YT alluded to, plants are rather finicky critters in a cultured environment. Bacteria and fungi will grow pretty much on anything, plants will not.

##### Share on other sites

if you are growing bacteria, don't do it at body temperature, or you could find yourself culturing pathogens, which is the badness.

##### Share on other sites
YT2095    591

I use an off the shelf product called "Gel 2 root", its not too expensive and is great for cloning your favorite plants (Chilis in my case).

it come pre-measured and has all the needed nutrients and growth stimulators for rooting. you just pop a littke hole in the tinfoil lid, and put you plant cutting half way into the clear gell, let it incubate for a few weeks, and youll see a new root ball form, you can then just plant it as normal

##### Share on other sites

HEY!!!!!!! so for growing bacteria you can just use normal tasteless gelatin....but i tried it and it never worked instead it just turned liquid:-(

##### Share on other sites
John Cuthber    3200

Gelatine is a protein and lots of bacteria can degrade it ( which is what Alwayshere found). Agar isn't the same , it's a polysacharide and many bugs can't digest it.

##### Share on other sites
Mr Skeptic    1154
HEY!!!!!!! so for growing bacteria you can just use normal tasteless gelatin....but i tried it and it never worked instead it just turned liquid:-(

It probably melted. Gelatin needs to be kept cool, though I think using less water helps with that.

##### Share on other sites
CharonY    1604

As John already mentioned, most bacteria dissolve gelatin (via proteases). It is not really suited for bacterial cultivation.

##### Share on other sites
Mr Skeptic    1154
As John already mentioned, most bacteria dissolve gelatin (via proteases). It is not really suited for bacterial cultivation.

Oh, so this is different than jello melting because it got warm. My bad.

##### Share on other sites
GLO531    10
Well, if you just want to plant seeds and move them to soil once they've sprouted, then the key thing is moisture and most plain agar plates should work fine so long as they are moist. (but then again, so will a moist paper towel) If, however, you want to regenerate whole plants from plant parts, or you want to do long-term plant tissue culture then you're going to need several other micro and macronutrients, and my advice to you at that point would be to buy it prepared from a science supplier because that will probably work out cheaper for you than having to buy every individual component. Unlike bacteria, as YT alluded to, plants are rather finicky critters in a cultured environment. Bacteria and fungi will grow pretty much on anything, plants will not.

Cookie...my son is doing the science expierment... where u grow bacteria from a dogs mouth and a humans, to see which is cleaner. It says I need agar. I dont have any science stores near me. You have any suggestions? Thx Gloria

##### Share on other sites
bonedog    10
Well, if you just want to plant seeds and move them to soil once they've sprouted, then the key thing is moisture and most plain agar plates should work fine so long as they are moist. (but then again, so will a moist paper towel) If, however, you want to regenerate whole plants from plant parts, or you want to do long-term plant tissue culture then you're going to need several other micro and macronutrients, and my advice to you at that point would be to buy it prepared from a science supplier because that will probably work out cheaper for you than having to buy every individual component. Unlike bacteria, as YT alluded to, plants are rather finicky critters in a cultured environment. Bacteria and fungi will grow pretty much on anything, plants will not.

hello all... im a newbie.. got a question. I have access to agar.R2a, and tsa,tsb and occasionally we throw out the expired media or give it to the local schools around here. I have lots of it at home. My curiosity is I would like to take some cuttings off pepper plants, tomato plants,etc and just stick them in straight tsa/tsb. Would the tryptic soy broth be a favorable environment to root those cuttings? also have liquid tsb in tubes.

also, would plant cuttings need to be "incubated"? I find this very fascinating and would love to hear any and all input anyone has on this subject. I apologize if this is in the wrong forum. thanx! bone

##### Share on other sites

On the subject of agar.. Have any of you heard of anybody combining agar and gelatin in one media? Does anybody know if one is soluble in the other?

I ask because I'm putting together some plates and slants to work with yeast, and I am horrified to find out just how expensive agar is. I'd like to try out a mixture to help reduce costs, but I'm wondering if that's going to be practical..

##### Share on other sites
CharonY    1604

Wow, that is an old thread. However, (as mentioned above) gelatin usually does not work well with microbes since most are able to degrade it and thus liquify the plates.

##### Share on other sites

That is a good observation.. However, I have a clean strain of S. cervasae that I'm working with, so I'm not overly concerned with any proteases that might liquefy the gelatin. I just haven't seen any information anywhere concerning the mixing of solidifying agents when preparing media, and this thread (as old as it is) seems to have a knowledgeable group discussing media preparation.

I'm just wondering if I could actually acheive a homogenous product if I combined geletin and agar. Although now that I'm really bringing the thinker into play, I might try to layer some plates- gelatin on the bottom, thin agar layer on the top.. My chief concern with the use of gelatin is the softness of the material, and how it will hold up to autoclaving (okay.. A trip through a pressure cooker). I want to keep my pure strains pure, you know..

##### Share on other sites
CharonY    1604

If the fungus degrades the gelatin you are not better off than with (mostly) liquid medium, regardless of the purity of your strain. However, there are different Saccharomyces strains, some of which are able to liquefy gelatin, some which are not. So you could be lucky.

There are a number of protocols that utilize autoclaved gelatin. However, it is possible that there differences in the heat stability of available gelatin types.

##### Share on other sites

Thanks for the information about other Sacharomyces strains, although I've never heard about a Saccharomyces cerevisiae (crevasse was an unfortunate auto-check error) that digests gelatin.. But I'm sure I haven't encountered them all.. Most home brewing literature suggests that gelatin is acceptable to preserve brewing yeast strains, so I've been working with the assumption that I'd be safe using it, so long as I wasn't dealing with an infected source. I suppose that I'd be better off with straight agar for media perpetration, even though in hindsight I suppose that agar and gelatin would probably mix just fine, as both are soluble in water.. *slaps forehead*

I love the extra information that I'm getting on this thread.

If I do try a mixture, I'll be sure to share my results..

##### Share on other sites
CharonY    1604

Ah, I see what you mean. You are correct that few yeasts are strongly proteolytic. I only remember that (way way back) we used a strain to demonstrate proteolytic activities (though not on gelatin). Something like strain 1532 or 1352 is in my mind, but my memory may be totally off.

##### Share on other sites

hello guys!

Biologist often use agar to plant things, and I would like to know how to make agar......

Thanks for any help in advance.

Specialty health food shops usually stock geatin powder. You use it at a concentration o 1-2% or 1-2g per 100ml of water.

Unlike gelatin it melts at about 80 degree clesius but wont solidify until the temp falls to about 35 degrees celsius - quite useful if you need to re-pot a seedling in fresh agar.

##### Share on other sites

Did they not used to use sheep's blood as an agar?

Im seriously not a biologist, and I have not had any training in pathology.

##### Share on other sites
Sorcerer    33

First you need how to select your agar.

Free range or wild agar is preferable.

Select a prime cut.

Take your agar, grill on a high heat to medium rare.

Enjoy.

##### Share on other sites
CharonY    1604

Did they not used to use sheep's blood as an agar?

Im seriously not a biologist, and I have not had any training in pathology.

Nope, agar is a polysaccharide derived from algae. Citrated sheep blood is used as a medium however (and can be mixed with agar to create plates).