Achieving different material properties (mycelium)

Hey there :slight_smile:

As an exhibit for a design exhibition, we want to create objects from mycelium, that vary in material characteristics. We hope to show, that it’s a versatile process that makes different properties possible.

As I’ve read, the species doesn’t influence the outcome too much, it should primarily match the substrate. Also, I guess we want to make grow conditions perfect for the mushroom, s.t. it grows through the substrate completely and to avoid contaminations. (Please correct me if I’m wrong!)

So I guess we will mostly play around with substrate and additives.

  • Substrate matter: Our first try was with soaked/welled rye which produced a very brittle material (whereas it was not fully grown-through). I imagine hemp fibers to produce something rather strong. There are many many options here, difficult to predict what will happen.
  • Substrate fineness: I would think that fine substrate gives a more rigid object, whereas it could be possible to achieve flexibility (at least in one direction) by using long fibers.
  • Additives: Maybe adding oil makes the material elastic? Maybe adding cut rubberbands will? Maybe its possible to add iron fillings to make it really heavy. Fire/Water resistance is something that many people are investigating, maybe we can also collect info about that here.
  • What else?

I would mostly like to stick to the hard material mycelium process but maybe kombucha/bacterial leather can be a good replacement for us for the exhibition in case the results are not so spectacular.

@Leen I’ve seen you made experiments with various natural materials. Did you notice any differences in physical properties?
@Elise Thanks for sharing your library, I have a lot to read :slight_smile:

I’m glad about any hints, ideas, experiences, thanks already!

Dear Jakob,

Nice to see that you are also bitten to make nice objects with mycelium.
I have indeed experimented with different natural materials. Bulky straw is not strong at all. It also goes very slowly and it falls apart. With plumes it is better. It does not fall apart and is solid. Shells only do not work well, combined with cardboard, it works well. Flax went even better than the coarse straw, but not really strong here either. Chopped wood goes quickly and weighs well and is firm. Of this I cut a piece in half. The middle part was not white. The seaweed did not succeed at all sides. Maybe it would work with freshly dried seaweed. It does not work with the pistachio nuts, and the potato peels have also failed. I hope you are something with this.
Friendly greetings,

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Hey Leen!

Thanks for this instructive overview. This is going to be very helpful!

The shells+cardboard makes me think: Maybe its a good idea to combine stabilizing/loosening/whatever (inorganic) stuff with mushroom food?

Yes indeed this is a good idea !


On the additivie front, I dont think rubber will give any more stretching that a loose fiber substrate would.

I have done some experiments with Ethylene glycol and glycerol soaks and they seem to add some flexibility.

Fire resistance is also a big plus, for celluose based materials the go to are borates, so you could try to soak them in borate solutions.


Hi Gamarra, thanks for your ideas!

Did you use pure Glycerol? Do you think it’s worth to try using glycerol as an additive during growth?

I don’t know if it’s a stupid idea, but what would happen if we add yeast (and sugar i guess)? could it make the object porous/fluffy? or will we just get contamination all over the place?

Another idea: Fizzy powder (Sherbet powder). It releases CO2 and Trisodium citrate and could form bubbles within the substrate dough. CO2 seems to help growth, but only up to 20-30% concentration. So 100% CO2 bubbles could do harm I guess.

Our workshop is on monday, so we’re happy about last minute ideas :slight_smile: And in case anyone happens to be in Vienna, you’re very welcome to join!

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both pure glycerol and ethylenglycol are easily degraded enough that they shouldnt give issues during growth.

The fluffy idea idea tuns into the issue that your matrix is not able to capture that CO2 fast enough to make a foam.

If your goal is to make a mycelium foam, the best option I could give you is to try to make a foam framework and try to inoculate that.

You could put yeast sugar and gelatine in one mold. and try the sherbet version in another. (make the gelatine first add the fizzy element as it cools down.)

that way (in my head you would have a foamy matrix that the fungi can eat and displace as it grows.)

The gelatine matrix sounds very cool, I’ll definitely check that out.

We ordered sawdust spawn, so I’m not sure how to inoculate, but maybe we can wash some spores out of the spawn, s.t. we can inoculate with a syringe? Or we take gelatine + sugar and at the right temperature add both sherbet + sawdust spawn together.

Thanks man :slight_smile:

I would try either what you described or spawn first, while warm, stirr so the spores are a bit mroe evenly distributed among the gelatine???

gelatine will slow down your growing times, most likely so keep that in mind.

Hhm, wikipedia says gelatin melting point is around 35°C, which is very close to (or above) the maximum temp. that I would expose the reishi to. I’ll take a thermometer and just decide then.

Gelatin needs refrigeration to fully settle most of the time so waiting until its 25 or so should be fine

Alright, sounds good! Thanks for your help.

I want to add sugar for one experiment, inspired by this paper. Can you guess a good amount? I will skip the potato extract, because I’d have to make it myself and the dextrose will just be an additive, not the sole substrate.

If I understand you are going for a sugar/cellullose substrate??

I wouldnt go straight sugar as that just makes it a very friendly substrate for bacteria and fungi have optimized for celullose digestion.

Instant mashed potatoes should do the trick in an emergency. (they are basically freeze dried and pulverized)

but I am just one of the house chemists, the actually growing part is not really my expertise area.

For most of the experiments (and for the objects the workshop participants will be making) we will use various dead plants etc. as substrate. We can add instant mashed potatoes/potato starch or pure sugar to some of them, just to try.

For the gelatine foam, I think a very fine substrate would be best, so ideally pure cellulose. At least for the yeast experiment we have to add starch/sugar.

Sorry if this is getting a bit confusing :upside_down:

@winnieponcelet In your manual, you add 1/10 coffee grounds (used I assume). I’m not sure we will collect enough until monday, do you know a replacment? Fresh coffee grounds after autoclaving should be the same, right?

You can also just leave out the coffee. It speeds up growth, but also increases contamination risk. It will work without these extra nutrients. Otherwise, you can add sugar or flour as well.

I have been playing around with mushroom growing and mycelium properties. I had some ideas on creating products to replace plastic usage at a low cost but as the project advances I ran into realization that Ecovative has 23-30 patents across 30+ countries on pretty much the whole mycelium material creation process. The patents pretty much covered final mycelium composite using any substrate, in any form, and with any mushroom variant. This is very discouraging and at the same time it explained why there aren’t any products that are mycelium based. I’m very heart broken by the fact that such a beautiful nature created material being patented by a company with large amount of money.

I truly believe that mycelium products will be world changing and will making the world a greener place for our future generation.