Tuesday, November 15, 2011

Growing Oyster Mushrooms - Cloning!

Cloning a sheep seemed a bit hard, so I figured I would start with a mushroom.  Anyway, how many Dolly's do we need?
Many mushroom species are ideal candidates for vegetative growth (or cloning if you prefer) since they naturally grow via mycelial networks.   
The basic idea is pretty simple.  Take a healthy, freshly picked mushroom, cut off a chunk of it, place it on a food source that the mushroom loves, and watch it grow!  Once the mycelium has grown to cover your growing medium, then you can take chunks of that medium and inoculate new food supplies.  Let the new chunks grow out in their fresh food source and repeat.  A tenfold expansion is common- so in 3 generations you can go from 1 to 10 to 100 to 1000.
Presuming you are adept at handling a few minor details like contamination, proper temperature, humidity, carbon dioxide levels, and supplying fresh sources of food as the mycelium needs- you can get some amazing results. 
In theory, you can go from a single chunk of mushroom to thousands of pounds in a few months, and millions of pounds within a year, becoming fabulously wealthy and successful. 
The reality of it is that while oyster mushrooms are vigorous, they have specific climactic needs.  Go outside the ideal window for any of a bunch of variables and you get a pile of mold, instead of tasty mushrooms.  I am not expecting success- but I have hope.  My goal is to just get the damn mycelium to grow successfully enough to get one new mushroom from it.

My protocol is based primarily off the work of Paul Stamets and Rush Wayne.  Paul has done more to encourage mushroom cultivation than anyone else in the US, and his books remain the bible of mushroom cultivation.  You can find links to them on the Amazon list on the right sidebar.  Rush Wayne has a neat protocol that uses the power of hydrogen peroxide to help prevent contamination.  This allows you to grow several species without the use of a HEPA hood- which can be a pretty expensive bit of equipment.

I made up agar plates using the malt extract agar mix from Fungi Perfecti, with the addition of 3 wood pellets and hydrogen peroxide.  For a full explanation read the work of the experts- they cover this far more thoroughly.
The recipe is as follows: (UPDATE- this seems to be a bit too much hydrogen peroxide- the growth onto agar is VERY slow- I will be trying it again with less peroxide).
(For 10 petri dishes)
25 grams Malt Extract Agar mix
3 wood pellets (hardwood pellets used in pellet stoves)
500ml filtered water
4ml 3% hydrogen peroxide

Combine the agar mix, pellets, and water in a flask/jar.  Cover loosely and pressure cook at 15 psi for 20 minutes.  Let cool until the agar mix is hot but you can handle it (say 110-140 F).  Add your hydrogen peroxide to the mix, and swirl it to mix.  Pour the agar into 10 clean petri dishes and let cool.  

Congratulations- you now have agar plates ready to use- that are in theory fairly resistant to contamination!

Oyster mushroom tissue on agar- day 2.
I then picked a healthy oyster mushroom and got out my surgery kit.  Or at least a scalpel and flame.  Flame sterilize your scalpel and cut open the mushroom.  The goal is to get a chunk of tissue from the inside of the mushroom (ideally near the cap) that has not been exposed to contaminants that may be on the outside of the mushroom.
Take your clean chunk of mushroom and place it on the center of an agar plate.  I did this to 5 plates- so hopefully at least a couple will be successful. 
I wrapped the other 5 plates in parafilm to help prevent contaminants from entering (although supposedly you don't need to do this), and put all ten of the plates in an open bag on a shelf.  65-75 is probably a good temperature for the mycelium to grow.

Day 8- primordia forming- but little growth onto agar.
Now we wait- growth should occur within a few days, and before two weeks have passed the mycelium should be ready for transferring to a larger volume, and further expansion of mycelial mass.

Day 2- Not much to report.  Possibly the slightest bit of growth onto agar- but not much.

Day 5- Little bumps forming on mushroom chunk- Primordia?  No infections yet.

Day 8- So the agar seems to have a bit too much hydrogen peroxide in it.  The mushroom is forming primordia from the initial chunk- but is very reluctant to grow out onto the agar.

Day 15- green mold growing on 1 plate.  Bummer!

Day 15- One plate has green mold growing on an edge- so I dumped it in the compost.  The rest are still contamination free- and actually starting to show good mycelial growth onto the agar.

Day 16- mycelial growth really getting going on this plate.