
Mylo: A leather-like material made from mycelium - tuanx5
https://boltthreads.com/technology/mylo/
======
nkurz
Coincidentally, a friend recently showed me his "mushroom hat", which is made
from "amadou":
[https://en.wikipedia.org/wiki/Amadou](https://en.wikipedia.org/wiki/Amadou).
It's a wonderful lightweight texture, somewhere between leather and felt. A
description of the manufacturing process (and the mushroom which it comes
from) is here: [http://frimminjimbits.blogspot.com/2012/08/mushroom-
cap.html](http://frimminjimbits.blogspot.com/2012/08/mushroom-cap.html)

~~~
sametmax
Wouldn't it be extremely flammable though? Raw amadou can burn even with the
smallest spark. We used to make lighters out of it.

~~~
alex_hitchins
This was my first thought. They must have some built in fire retardant layer.
Otherwise you a cigarette burn would set you alight. Interesting point, I'm
not sure how fast it burns. It might just smolder away. Still not desirable!

~~~
sametmax
It's slow and not very "flammy", so it wouldn't turn you into a torch.

------
baxtr
Leather production comes at a very high cost to the environment. So I welcome
any real alternative (assuming it is significantly less dirty).

[https://undark.org/article/leather-tanning-bangladesh-
india/](https://undark.org/article/leather-tanning-bangladesh-india/)

~~~
gehwartzen
Won't that leather still get used elsewhere? I don't think many animals are
reared with the primarry intent of producing leather but rather becouse of our
high meat demand and we can't make one without the other.

~~~
CamperBob2
It will be interesting to see what happens over the next decade or two, once
synthmeat is good enough to take over the market. Various breeds of cattle
will likely go extinct, and the same social opprobrium that will wipe out the
market for "real" meat will presumably affect leather goods as well.

~~~
malydok
When synthetic meat becomes good enough there'll still be loads of people
who'll say it's inferior to the real thing. Apart from that I believe a happy
cow is better than no cow so sustainable and environmentally-friendly
livestock farms still have a reason to exist.

~~~
virgilp
Well, already you have "loads of people" claiming that kobe beef is better
than regular beef (or that the black iberian pig is better than other kinds of
pig). Yet, since meet from those animals is expensive, in practice the vast
majority of meat doesn't come from these species.

It can be identical with synthetic vs natural meat. Price can make the
difference, and we can still reduce massively the amount of livestock we breed
(e.g. make the farms more environmentally-friendly through regulation)

~~~
KozmoNau7
>"Well, already you have "loads of people" claiming that kobe beef is better
than regular beef _(or that the black iberian pig is better than other kinds
of pig)_. Yet, since meet from those animals is expensive, in practice the
vast majority of meat doesn't come from these species.

Having just been on vacation in Malaga (highly recommended), Jamon Iberico
Bellota -- the highest-quality ham from acorn-fed black iberian pigs -- is
absolutely, genuinely so superior to lesser hams that it's not even funny.
There is just no comparison.

It also costs at least €130/kg even the smallest local ham stores, so yes it
is prohibitively expensive, you can expect to pay at least twice that for the
genuine stuff, if you're not in Andalusia.

How much of the taste is because the diet, and how much is because of the
breed? Who knows, but I think it's a combination.

~~~
pista
It is and there are official classifications for that. _Ibérico_ is about the
race, _pata negra_ (black paw) being a best subclass name that expanded to
anything first class. If a Spaniard says you are _pata negra_ , it's actually
good, not an indictment on your feet higiene :)

Bellota (acorn) the diet. You can find intermediate categories like "50% raza
ibérica" or "recebo" for both.

~~~
KozmoNau7
Oh yes, I got a very thorough explanation and examples from a very dedicated
ham shop owner. It was a bit of a lazy afternoon, so he took the time to
properly school us on every detail and the classification system.

If you're ever in Malaga, hit up Azabache in the old part of town. One hell of
a shop for ham and cheese and a bit of seafood.

------
Kluny
"It’s strong, and abrasion resistant." As a motorcyclist, I need to see a
side-by-side abrasion resistance comparison. So far, nothing beats leather.

~~~
gcb0
technically toilet paper is "strong, abrasion resistant".

But since they did not mention durability anywhere on the marketing speak,
that means even their marketeer couldn't find a way to lie about durability
qualities. Unfortunately nothing to see here :(

~~~
taberiand
Also read between the lines about biodegradability - I'm betting this stuff
breaks down relatively quickly?

~~~
sametmax
Like leather. We treat leather.

------
ggm
Can somebody explain how this is different to the "pleather" being made as a
side-product from the production of Kombucha? Thats been a thing for a while
now.

AFAIK its also grown by mould, from culture. But, it forms as a mat on top of
the Kombucha fermenting liquid.

~~~
jfarlow
(please help me where I'm wrong other scientists... But here's my basic
knowledge.)

Leather as you know it are combinations a few different (known) structural
proteins secreted from mammals between skin cells, after the skin cells
themselves have been removed, and the proteins become chemically glued
together (cross-linked). The majority of that protein is collagen.

Plether is a plastic fiber (petroleum derivative) that is spun and processed
in such a way as to have an appearance similar to the final leather product
(kind of, close enough). It's not protein-based in any way.

This new leather, 'Mylo', is a protein-based 'fabric' where the base protein
is secreted by fungi rather than mammals. However, fungi are similar enough to
mammals evolutionarily, that the proteins they secrete are evolutionary
related to those secreted by our own cells to make our skin. The primary
protein in both cases is collagen. Additionally, fungi genetics are easily
manipulable, so you can actually insert the DNA that encodes for mammal-like
collagen, other proteins found in animal leather, or proteins with new or
completely different functions that would never show up on the skin of a
mammal (color, water resistance, enzymatic capabilities, etc.).

tldr: Pleather is nothing like animal leather chemically - but has some
similar bulk properties. This new MyLo is chemically related (evolutionarily)
to animal leather, but ultimately comes from fungi. _But_ because it's
genetically known, it can actually include new capabilities that cannot be
found in animal leather.

~~~
tomkinstinch
Yes, like us, fungi are opisthokonts, but where collagen is the mammalian
structural protein used for making leather, fungal hyphae are principally
comprised of chitin—structurally closer to the polysaccharide cellulose of the
mentioned "kombucha leather" than to the collagen protein. Collagen is present
in fungi in certain edge cases, but bulk mycelium is mostly chitin. This is
speculation, but leather made from chitin may actually be a bit stronger than
animal leather made from collagen. Maybe closer to keratin in strength?
(Interestingly, keratin is chemically cleaved in hides during leather
production--not entirely sure why, to enhance flexibility and allow access to
the collagen fibers?). Agreed about fungi being easier to engineer. As you
point out, endogenous expression of dyes in hyphae for different colors of
mycelial leather is compelling. GFP would be cool too for the rave and
nightclub crowd.

The Quorn meat analogue[1] is another product made from compressed mycelium.
I've had "chicken" nuggets made from it. They're...not bad, but as far as
mycelial structures go I prefer mushrooms.

1\.
[http://www.misac.org.uk/PDFs/MiSAC_Briefings_1.pdf](http://www.misac.org.uk/PDFs/MiSAC_Briefings_1.pdf)

------
italophil
I believe they licensed the mycelium technology from a NY based startup called
Ecovative, that has been shopping it around for furniture for some time.

~~~
BLanen
Correct.

Proof: website:
[https://www.ecovativedesign.com/](https://www.ecovativedesign.com/)

------
scythe
The problem with pleather, in my experience, isn't that it feels
insufficiently leather-like. The appearance is also just fine; the tendency to
fade actually produces a somewhat nice pattern. The real problem is that the
durability of most fake leather is drastically inferior to natural leather.

From personal experience, I had a leather jacket which I got in my first year
of college (2008) and wore until it was stolen from my car in early 2016, when
it was still in nearly-perfect condition (although the zipper got worse). I
replaced it with a pleather jacket which has already lost most of the material
on the right elbow and may soon develop a hole.

So I hope this mushroom-derived material will be at least _somewhat_ more
durable. What I really want to see is a sort of fake leather made from a more
resilient polymer, such as polyetherimide or one of the other "high-
performance polymers". Until that situation improves, I think I'm going back
to cowhide.

~~~
NovaS1X
The durability isn't just a nice feature, but for motorcyclists is essential.
I haven't found anything that comes close to the abrasion resistance that
natural leather has (while looking like a leather jacket, not including things
like kevlar for example).

Top it off with durability that can seriously last a lifetime and look better
with age, there's no real competition in the synthetic leathers that comes
close to the real thing.

~~~
foobarian
I'm not a motorcyclist, and I noticed multiple comments mentioning durability
of leather is important for motorcyclists. How come? Is falling off a common
thing with motorcycles? It sure isn't very common with bicycles or cars.

~~~
skellera
I don’t think it’s about how often. It’s about that one time it happens, you
want protection. The skid distance on a motorcycle isn’t comparable to a
bicycle.

------
rdlecler1
Interesting, although on the business side, what happened to the spider silk?
Bolt closed a $125m round in November 2017. You only get that kind of money if
you are a messianic founder or have lots of progress.... This feels like this
is some kind of auxiliary parachute. I wonder if the investors knew. Ironic
that Peter Theil’s Founders Fund was one of the investors.... “We wanted
spider silk and instead we got mushroom leather.”

~~~
ampersandy
They have a separate section on their website describing their Microsilk,
which is being used to produce ties.

[https://boltthreads.com/technology/microsilk/](https://boltthreads.com/technology/microsilk/)
[https://ties.boltthreads.com/](https://ties.boltthreads.com/)

~~~
rdlecler1
This is just speculation, but this looks to be in a “coming soon” state. They
could be having any number of issues, including scaling, cost reduction, and
the macro properties of the fabric may not have lived up to the early
promises.

------
weatherlight
This is exciting for new leather products, I'd like to see how a pair of
boxing gloves or a pair of Thai pads made from such a material hold up. As for
other leather goods. I usually just buy them second hand from a goodwill or
something. Almost, Second-hand anything is good for the environment.

~~~
ainiriand
Second hand leather is better for the environment that this product, that is a
fact.

~~~
weatherlight
that's what I was trying to communicate! :)

------
toufka
Very fun. A number of new players here. I look forward to the more exotic
possibilities downstream. Integrating other biological capabilities, relaxing
size, thickness, supplychain constraints, being part of a genetically-dynamic
R&D process.

I'm curious about the different approaches between Bolt (who've so far at
least been focused on fermentation) and Modern Meadow - versus newer smaller
players like Provenance.

[http://www.modernmeadow.com](http://www.modernmeadow.com)

[http://provenance.bio](http://provenance.bio)

------
ajkjk
Is it absolutely necessary to always write (tm) after every Mylo? It's so
distracting. And, well, corporate. It's gross.

How do we get to a world where we can stop doing that? Or do we already live
in one and not everybody knows?

~~~
pbhjpbhj
They're asserting their trademark, using TM is legally impotent in the UK.
Trademarks are trademarks, their legal status changes with registration when
you get to use RTM.

Don't know if it works in other countries I assume it's different in USA,
maybe affects damages?

------
anfilt
Funny thing I am not sure what fungus it is. However, I have pulled small
sheets of material that is almost like leather out from beneath the bark on
firewood when splitting it. It's very white kinda soft too.

I wonder if this is the same thing, and then they just dye it.

-Edit- It usually looks like this, but sometimes grows into like a sheet between the bark, and wood. [https://projects.ncsu.edu/cals/course/pp728/Armillaria/fans....](https://projects.ncsu.edu/cals/course/pp728/Armillaria/fans.gif)

------
calibas
Cool product, it just bothers me that they describe mycelium as the
"underground root structure of mushrooms". That's like saying the rest of a
plant is just part of a flower.

~~~
coldacid
Yep. The truth is, mushrooms are really just the sex organs of mycelium.

~~~
mda
More accurately, "Fruiting bodies".

------
BadassFractal
I found the conversation between Paul Stamets and Joe Rogan to be super
interesting:
[https://www.youtube.com/watch?v=mPqWstVnRjQ](https://www.youtube.com/watch?v=mPqWstVnRjQ)
. Never really thought much about mushrooms until that episode. This proof of
concept seems like a great taste of how much untapped potential fungi have for
changing everyday life if we invest more into its research.

------
ineedasername
Keep in mind, this only obviates one of the "sustainable" aspects of leather
production, the raw untanned hides. From an environmental perspective its
chrome tanning and dyeing that are the big hitters, and that would still be
necessary here. They could veg tan it instead, but that only slightly lessens
the environmental impact at significantly higher cost.

------
otakucode
Would this be a good candidate to use as a synthetic skin for touch-able
robots and devices? I've thought for awhile that leather might be good for
that, but something like this which could be grown with electronics, heating
elements, and other things embedded directly into it would probably be much
better!

~~~
hughes
It's very inelastic. Good skin will probably need to stretch reasonably well.

------
amelius
Perhaps a silly question, but what does it smell like?

~~~
throwaway413
Exactly what I wondered as well.

------
etrautmann
This is incredibly exciting from an environmental standpoint alone, let alone
the implications for future materials research. I'm curious about the
processing steps required to create the end product and the resulting
durability.

------
nautilus12
Simple question that they didn't answer anywhere: how long until your mylo
jacket degrades into mushroom goo?

~~~
ARCarr
"We will undertake a full lifecycle analysis of Mylo™ prior to large scale
commercial rollout, and we look forward to sharing those findings with the
world."

I'm assuming this also means finding out how long 'til it disintegrates.

------
carbocation
In their FAQ, I think they should address the question, "Is it possible that
mold will grow from Mylo?" I'm sure the answer is no, but they should state it
explicitly.

~~~
ygra
Considering it's still tanned the same way, that process will probably
preserve it and prevent mold growth, just as with leather.

------
ChuckMcM
Very cool, but really wonder what the durability is. Is it more like faux
leather which might be used as an accent or is it something you could actually
use structurally.

------
verytrivial
This seems to be another application of the organism used for the meat-
substitute sold under the brand
[https://en.m.wikipedia.org/wiki/Quorn](https://en.m.wikipedia.org/wiki/Quorn).
(Which is rather tasty when prepared right).

------
dzhiurgis
One thing I do not get about leather is why do people like it?

One sibling comment mention durability. But otherwise I find it's very heavy,
cold, not breathable, sensitive to water and doesn't really look that well.

Sure I do prefer suede office shoes over normal leather, but that's about it.
There are probably some good industrial use cases, but I much prefer Gore-tex
type of materials and especially Merino wool. It's breathable, doesn't attract
smell, somewhat water resistant, doesn't hurt animals too much and is close to
cotton. I am rarely into clothing brands, but Icebreaker and Allbirds are
making really good stuff that I've been wearing non-stop for years now.

~~~
qkls
Looks is an opinion but at least it ages better than most materials. Old
leather belts or watchstraps look fine after many years of use.

------
JonRB
It's awesome to see some more players in this space. I've been keenly watching
out for Modern Meadow's updates as well. Looking forward to seeing what this
will bring!

------
zarify
I wish one of their FAQ down the bottom was about water resistance.

~~~
mod
There's probably a good reason they didn't mention that, or durability.

I do some leatherwork for fun and there's a lot of things that make it hard to
replace. We'll see how it holds up when stitched.

I'm very open to trying it out, though. And maybe an upholstery waterproofer
would do the job.

~~~
jfarlow
The fun part here is that, technically, once they get a 'good enough' product
and workflow up and running, adding/changing/incorporating biological
properties is (mostly) just a DNA-based bit-flip away.

We at Serotiny are already collecting protein domains from organisms with
various capabilities - including water solubility, hydrophobicity, enzymatic
capabilities, covalent attachment sites (for dyes), light-activated
properties/crosslinking/dissociation/etc. And all of those protein domains
we're collecting should be 100% compatible (+/\- a fair bit of a tooling-
exercise) with both Bolt's leather and their silk.

So it should get fun once they have a solid and stable 'platform' up and
running. They will be able to incorporate most any property from _nature_ with
an existing proof of principal, not just any property form _mammalian hides_.

Congratulations guys!

------
indescions_2018
Congrats! This looks like a home run.

Would love to see micrographs of the finished materials. Fungi possess
wonderfully dense cobweb-like fibres. A terrific example of highly connected
random graphs in nature!

[https://www.researchgate.net/figure/Scanning-Electron-
Microg...](https://www.researchgate.net/figure/Scanning-Electron-Micrograph-
of-mycelium-viewed-at-approximately-100x-Credit-Paul_fig1_271214237)

------
ValleyOfTheMtns
With lab grown meat on the horizon as a main stream consumer product, it's
only natural to wonder whether we could also grow lab grown skin to create
synthetic leather.

Perhaps that defeats the purpose of mushroom based "leather" though? You might
be able to grow the skin artificially, but it will still need to be tanned at
an environmental cost.

~~~
KozmoNau7
That all depends on which process will be cheaper and which material will have
the most desirable properties. I certainly hope the competition fosters better
products in the end.

------
Lazare
Super interesting! However...

...my impression (not dispelled or even challenged by their marketing
materials) is that we currently have effectively surplus hides as a side
effect of raising animals for meat, milk, and other purposes.

So when they say:

> Livestock use an astonishing 30% of the earth’s entire land surface and
> cattle-rearing generates more global warming greenhouse gases, as measured
> in carbon dioxide equivalent, than all transportation methods. Put simply,
> as disposable incomes rise around the globe, we simply can’t meet the demand
> for meat — and leather consumer goods — using resources available on the
> planet.

That seems to be about 90% true (but irrelevant) and 10% questionable.
Livestock are very expensive environmentally, and as the world gets richer we
will certainly struggle to support the current meat-heavy western diet for
billions more people. But that still means we're going to be producing an
enormous torrent of hides (more now than today). Are we really going to
struggle to find enough _hides_ to meet global demand for leather good? Prices
for raw inputs have been remarkably flat for the past ~20 years
([https://fred.stlouisfed.org/series/WPU04190108](https://fred.stlouisfed.org/series/WPU04190108)).

Even from the perspective of minimising animal cruelty, leather from animals
that would already be raised and killed for meat or because they were ending
their useful life on a dairy farm isn't especially problematic.

Further:

> We carefully control the mycelium’s growth conditions to produce a substrate
> that can be cured and tanned into a soft, supple material that looks and
> feels like leather.

So it still needs to be cured and tanned. Which no doubt helps it be a great
leather substitute, but much of the cost (monetary and environmental) of
leather isn't the hides, it's the curing and tanning process, which can use
some pretty harsh chemicals. Another reason to be skeptical that this is a
huge improvement environmentally.

I also note there's no real discussion of price. If this process can turn out
finished leather more cheaply than traditional methods, that's a big sign this
is more efficient environmentally. If it can't (and the silence is
interesting), it raises the question of whether this is actually worse for the
environment. (Which wouldn't be that hard to imagine!)

In short: Totally cool! But so far it doesn't look like a "we're going to get
rich while saving the planet" kind of thing, more like a "maybe some vegans
will pay a premium for a really good fake leather jacket" kind of thing. Also
good! But not as amazing as they try to make it sound.

~~~
apendleton
Maybe it makes more sense to view this in concert with other similar efforts
to address different uses of livestock? Like, to replace all the uses of a cow
with synthetics, you need lab-grown meat and lab-grown milk and lab-grown
leather, and ...

And there are startups addressing each of these, independently of one another.

~~~
coldacid
Until we're at that point, though, we're going to keep growing cattle the old
fashioned way, and that means leather to spare.

~~~
apendleton
Sure, but it'd be a shame to reach that point on the meat front and then still
have to keep growing cattle for the leather while the textile technologies
catch up. Why not do both now?

~~~
coldacid
Chances are you'd be growing a whole mix of cow parts at first and have to
figure out how to differentiate them for the vats, so I doubt it'd be a
problem. By the time vat meat works properly, you'd probably have the right
knowledge and tech to grow cow hide by the mile simultaneously.

------
splitrocket
This is the future I want.

------
devilsattitude
I've gone through the entire article and have taken a moment to check the
links and it's amazing very organic and very astonishing nature has the hidden
gems for us discover.

~~~
inteleng
What?

------
lmilcin
One of those things that feels completely obvious in retrospect yet I envy
person that has the mind to think you can grow mushrooms and make leather out
of it.

------
skykooler
I'm curious as to how this handles high temperatures. Almost all welding
gloves, aprons etc. that I have seen are made of leather due to this property.

------
lucisferre
Today: Leather; Tomorrow: Space travel!

------
nn3
How do they kill the fungus? I hope it won't continue growing if you wear it.

~~~
pohl
If the cow doesn't, why would the fungus?

~~~
PeterisP
Random tiny fragments of cows don't cause cows growing around my house or on
my stuff. Fungus/mold does that.

~~~
paulific
That sounds like a great science fiction story though!

------
Annatar
I wish they were taking on investments; I want to sink some cash into them.

------
jeffreyrogers
Two most important things that were left out are durability and price.

~~~
flamtap
That was my immediate question, as leather is one of the most hard-wearing
upholstery materials available. As far as price goes, at first blush I would
imagine this would scale fairly well, at least much better than livestock.

------
2_listerine_pls
Is it patented?

------
barkingcat
Allows you to travel at warp factor 13!

------
classics2
Tensile strength, tear resistance?

------
ommunist
Interesting. But I cannot see any table with reference to mechanical
properties of the new materials. MycoWorks instead shed some light upon it on
their website. They are using strains of Ganoderma lucidim, and it can be
tanned while it grows, not after.

~~~
seltzered_
I went down a rabbit hole, and stumbled upon
[http://www.mycoworks.com/](http://www.mycoworks.com/) as well which is
seemingly an earlier competitor. Particularly their resources & reading
section at the bottom references a number of papers on the subject.

------
igitur
Insert obligatory Star Trek Discovery reference here.

~~~
DoTheNeedful
Or Dune

