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ATWAR
Connoisseur

Registered: 01/26/03
Posts: 1,640
Loc: #108768 in line...
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Agar: Malt concentrations and supplements...
#2837837 - 06/28/04 09:47 PM (20 years, 7 months ago) |
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Ok, I have been using a 2-3% malt concentration in my agar for a long time, and have had no trouble, finally settling on an additional 0.5% concentration of Dextrose as well. Now since I have decided to use rye or straw in my agar as well (typically 0.5% for each supplement), It has me wondering about concentrations of such ingredients when combined. Typical recipe is: 200ml water, 4 grams malt, 1 gram dextrose, 1 gram Yeast, 1 gram powdered substrate or 1ml of a true substrate extract.
I am curious to know when you would start to run into diminished returns adding additional supplements, I.E. - at what levels would start to hinder growth. What happens if I make a 10% malt concentration for example? Is there an upper limit (or an ideal limit) to where I should balance my total sugar and carbohydrate concentration?
In TMC Stamets mentions an agar mix utilizing boiled rye supplemented with malt, but does not go into further detail. Basically I would look at it like a recipe I used in reverse, 4 grams malt to 1-2ml rye extract. Anyone have a suggestion on where I would start with this? I have no clue how much rye to water ratio to use when boiling, how long, or how much malt to add. Stamets likes to leave us hanging I guess or more importantly, figure it out on our own (which I don't want to do, I have enough experiments going as it is).
Next question: One thing I don't think I have ever seen covered is how "solid" should the agar be? I personally have had different brands and some premixes come out hard like wax almost, while others are just like jello. I also notice Stamets mentions when making slants he "doubles up on the formula so the agar gels sufficiently" (GGMM, I assume he only means agar). I use 5 grams agar for my dish mix, and this usually leaves me with an agar much harder than jello, but still soft and squishy. I add an additional gram when I make culture tubes, usually always about 6-7. It becomes quite a bit firmer than jello, almost rubber like. What is an ideal "hardness" level, or does it really matter that much? Will the mycelium still colonize it just as well if I were to increase up to 8 grams agar?
Last question: I am at the stage where I would like to alternate my media recipe for each transfer, helping with mycelial vigor and reducing media selectivity. I can definitely notice the leap-off time is reduced by at least a day using rye extract in my agar when transfer a wedge to a jar. I have a curiosity that since the mycelium was currently digesting nutrients in the grain agar, it had no problem grabbing on to a rye kernel. But what about later transfers, say I use OMYA with no grain. This "new" mycelium would not currently be in the process of digesting rye nutrients, but would it still retain a "memory" for the substrate, thus recovering and taking to the grain in a shorter time as I have observed? I ask that because I wonder if I am wasting my time powdering straw for agar that gets transferred to grain...
Ok wait, one last quickie: Is peptone worth the extra time to weigh it out?  I have 25g on the way to try it out, which is more than enough to last me for awhile. Does it help with the vigor in a noticeable way?
Sorry for the long wind, its my nature I guess...
-------------------- To give is to live...
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Alien
Galactic Shaman


Registered: 11/14/99
Posts: 1,868
Loc: Jupiter's Moon
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Re: Agar: Malt concentrations and supplements... [Re: ATWAR]
#2839323 - 06/29/04 10:11 AM (20 years, 7 months ago) |
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> I have no clue how much rye to water ratio to use when boiling, how long, or how much malt to add.
Here is a formula for water culture, maybe you could work from it.
Save cooking water from a Batch of Rye. (I do NOT recommend pasteurization water from straw as some have suggested) Let stand in sealed jar in fridge overnight to collect sediment at the bottom. Pour the clear top fluid into another flask. Dilute till the liquid is clear golden as opposed to darkish brown. I add 4% dextrose by wieght (assuming water and rye cooking water have the same specific gravity which they don't (i told you this was rough) you can equate 1cc = 1gm or 40gms dextrose per litre). Mix well, pour into pint jars halfway up, sterilize for 30 mins at 15psi. Inject whatever culture/spores you have. Should be done in 2 weeks at the out.
> One thing I don't think I have ever seen covered is how "solid" should the agar be?
Personal taste, I prefer just past the jelly stage, basically like jello that is left out for a day and gets that tough layer on top, thats where I like it.
-------------------- -Alien
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tubervegan
Stranger
Registered: 07/02/04
Posts: 76
Last seen: 10 years, 9 months
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Re: Agar: Malt concentrations and supplements... [Re: ATWAR]
#2856777 - 07/04/04 04:43 PM (20 years, 7 months ago) |
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Yeah professionally made agar, on a scale from wax to jello, is about 3/4+ the way to jello.
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micro
bunbun has a gungun


Registered: 05/09/03
Posts: 7,532
Loc: Brick City
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Re: Agar: Malt concentrations and supplements... [Re: ATWAR]
#2856803 - 07/04/04 05:01 PM (20 years, 7 months ago) |
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Quote:
Yeah professionally made agar, on a scale from wax to jello, is about 3/4+ the way to jello.
It this the Jello scale? I think I read something about theat in Science.... 
Seriously, though, I think you're using too much agar. I usually use 15g per liter but up to 20g is fine. Divide by 5 for 200 mL and you should be using maximum 5g, but you could be using 3.75g for 200 mL -- I would recommend staying closer to that, as long as it solidifies.
As far as additives and stuff are concerned, you want the carbon:nitrogen ratio around 10:1 -- any less promotes waste accumulation. You don't want too many water solubles, either, as it will screw up the osmolarity. If you want to add other stuff, trade it for something, i.e. add less malt, but you're really making a judgement call unless you have specific information about the molecular constitution of the additive. The best bet is to stick with time-tested recipes unless you have a reason not to -- MEA and PDA work fine without additives unless you're trying to cultivate a strange genus/species.
-- Micro
-------------------- Any research paper or book for free
(Avatar is Maxxy, a character by Mizzyam, RIP)
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matts
matts

Registered: 01/28/02
Posts: 3,649
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Re: Agar: Malt concentrations and supplements... [Re: micro]
#2856831 - 07/04/04 05:21 PM (20 years, 7 months ago) |
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ATWAR
Connoisseur

Registered: 01/26/03
Posts: 1,640
Loc: #108768 in line...
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Re: Agar: Malt concentrations and supplements... [Re: micro]
#2857042 - 07/04/04 07:51 PM (20 years, 7 months ago) |
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Quote:
micro said: Seriously, though, I think you're using too much agar. I usually use 15g per liter but up to 20g is fine. Divide by 5 for 200 mL and you should be using maximum 5g, but you could be using 3.75g for 200 mL -- I would recommend staying closer to that, as long as it solidifies.
Thus the reason why I use 5 grams instead of 4 as most recipes in TMC and GGMM call for. 4 grams and less agar in 200ml water does not solidify to the texture I want. Basically just a little harder than jello so I can spear it with a scalpel without it falling apart. I have had some batches come out soft, and I have purposely made it rubbery for culture tubes. I really noticed no difference in colonization. I was just curious about this as Stamets says he doubles up on the mix for tubes. This got the gears turning in my head wondering if there is an ideal consistancy to use, or if it really matters...
-------------------- To give is to live...
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micro
bunbun has a gungun


Registered: 05/09/03
Posts: 7,532
Loc: Brick City
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Re: Agar: Malt concentrations and supplements... [Re: ATWAR]
#2857056 - 07/04/04 08:07 PM (20 years, 7 months ago) |
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Maybe it's just the type of agar, then? It should never come out like wax -- that's way too hard.
I've never heard of anyone going over 2%, but if it works, it works.
-- Micro
-------------------- Any research paper or book for free
(Avatar is Maxxy, a character by Mizzyam, RIP)
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ATWAR
Connoisseur

Registered: 01/26/03
Posts: 1,640
Loc: #108768 in line...
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Re: Agar: Malt concentrations and supplements... [Re: micro]
#2857068 - 07/04/04 08:20 PM (20 years, 7 months ago) |
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Well, more like rubber. Not really like wax, I just used it as an inappropriate example. I just prefer mine to solidify enough so I can spear it without falling off. 5 grams gives me this consistency, while 4 grams comes out just like jello which does not have the hardness I desire. I ordered some 3 section dishes along with my peptone so I could do a few experiments testing the colonization of various mixes. I will include agar hardness as well...
-------------------- To give is to live...
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