Chapter 24: Commercial Exploitation of Fungal Metabolites and Mycelia

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Welcome back to the Deep Dive.

Today we're diving into a kingdom that's, well, often overlooked yet secretly underpins so much of our modern world.

When we talk about exploiting resources, it can often sound a bit negative,

but with fungi,

it's a different story.

We're actually talking about the incredible ways humanity has learned to sort of partner with one of nature's most versatile resources.

Our mission today is to take a real deep dive into the commercial leverage, the use of fungal metabolites and mycelia.

We'll show you how these microscopic and macroscopic marvels aren't just useful, but absolutely essential.

Think of this as your shortcut to understanding the surprising impact of fungi with plenty of illuminating insights along the way.

That's right.

For centuries, our commercial interactions with fungi were relatively simple, you know, growing edible mushrooms or using fermentation for drinks, pretty straightforward stuff.

But as we'll explore today, especially since the serendipitous discovery of penicillin, the landscape of what we call fungal exploitation has just exploded.

What's particularly striking, I think, is that fungi, especially those grown in pure culture, represent an amazing renewable resource.

They readily germinate, I mean, from almost infinite supply of spores.

They grow on a wide range of surplus materials like the gas you mentioned, the leftovers from sugarcane, and they possess this incredible spectrum of enzymes that can break down or synthesize complex compounds.

And that biological versatility is just the beginning, isn't it?

Our goal today is to walk you through the astonishing breadth of fungal applications from, you know, lifesaving medicines to the very materials that might build your next So let's unpack this fungal phenomenon.

Let's begin with a genuine game changer, antibiotics.

You might not know her name, but Anne Sheaffer Miller's story is the perfect entry point to understanding their impact.

In March of 1942, she was critically ill, delirious with a streptococcal infection.

For a month, doctors had exhausted every option, sulfate, drugs, transfusions, even surgery.

Nothing worked.

It really seemed the streptococcus bacterium was about to claim It was indeed a desperate situation.

Really desperate.

But then, just as all hope seemed to be fading, her doctors managed to get hold of a newly purified fungal metabolite, penicillin.

This compound, named for the penicillin mold that produced it, was administered to Anne.

And remarkably, her temperature dropped, she emerged from delirium, started to eat again.

Her hospital chart, which records this incredible turnaround, it's now preserved in the Smithsonian.

It's such a powerful testament to one of medicine's greatest triumphs.

She was incredibly lucky, getting it just in the nick of time.

That's an incredible rescue story.

But what's even more intriguing, maybe, is the backstory to penicillin's discovery.

Because while Anne Miller's life was saved in 42, penicillin itself was first observed much earlier, right back in 1927, by Sir Alexander Fleming.

He noticed a staphylococcus aureus culture plate.

Basically, a dish -growing bacteria had become contaminated by a mold.

And around this fungal colony, there was this wide, clear zone where the bacteria just weren't growing or were killed off.

He isolated the mold, identified it as penicillin notatum, and named the substance penicillin.

Exactly.

And this concept of anti -biosis, where one organism makes stuff harmful to another, it wasn't entirely new.

John Tyndall had noted it way back in 1881.

But Fleming's observation led to the crucial test, finding something that was way more damaging to bacteria than it was to human cells.

Penicillin fit the bill perfectly, especially for what we call gram -positive bacteria.

That's a class of bacteria identified by how their cell walls react to a lab stain.

Fleming published his findings, but kind of surprisingly, he didn't really pursue its therapeutic use much further at the time.

It really makes you wonder how close we were to missing its potential altogether.

The urgency of World War II, with its desperate need to treat wounded servicemen, that really accelerated its development.

That pushed things forward.

By 1941, they had isolated measurable quantities.

They even used it on a police officer with a fatal infection, though, sadly, he relapsed when the supplies ran out.

But then a collaboration of British and American scientists, backed by the Rockefeller Foundation, they really jumped into scale of production.

They discovered penicillium chrysogenum, produced way more penicillin than penotatum, and pretty soon mass production began.

That's what provided enough to cure Anne Miller and eventually millions of others.

And this massive effort, this collaboration culminated in Fleming, along with Howard Flory and Ernst Chain, who were the ones who really isolated and characterized penicillin for therapeutic use, sharing a Nobel Prize in 1945.

And what followed was just an explosion of innovation.

You had the natural penicillins like GNV, but then they were quickly joined by semi -synthetic versions, things like phenethicillin, which was absorbed better, and others like methicillin, ampicillin, amoxicillin.

These had broader activity against different bacteria.

By 1951, global antibiotic sales were nearly $350 million a year.

That figure has just soared into the billions since then.

And the antibiotic story didn't stop with penicillin, did it?

In the 1960s, a new type of beta -lactam antibiotic emerged,

cephalosporin.

That name refers to its chemical structure, right?

It had that beta -lactam ring, which is key to how it works against bacteria.

Exactly.

It was isolated from a fungus called cephalosporin, which we now call acrimonium, and it was effective against some gram -negative bacteria, which penicillin wasn't always great against, so it further expanded our arsenal.

And just like penicillin, it underwent diversification to improve activity and fight off bacterial resistance mechanisms.

Okay, so we have these amazing drugs, but how do they actually work?

How do penicillins and cephalosporins stop bacteria?

Well, the beta -lactams, that whole group, they basically prevent bacteria from building their cell walls properly.

So they don't necessarily kill the bacteria directly, not always, but they weaken them significantly.

This allows the body's own immune defenses, you know, the white blood cells and so on, to catch up and eliminate the pathogens.

We also have antifungal antibiotics like grizofulvin.

That comes from penicillium grizofulvum, and it's taken orally to combat stubborn skin infections like tinias.

Grizofulvin works a bit differently, damaging fungal membranes.

It's fungistatic, meaning it inhibits fungal growth rather than killing outright.

Other antifungals like nystatin and amfotericin B are fungicidal.

They actually kill fungi by damaging the sterile components, crucial parts of their cell membranes.

But the story of antibiotics, as amazing as it is, also carries a serious cautionary tale.

Ann Miller lived to be 90, she passed away in 1999.

And in her lifetime, she saw the rise of many penicillin resistant bacterial strains.

A huge problem.

Strains like MRSA, methicillin resistant staphylococcus aureus.

They're now a massive issue in hospitals, extremely difficult to get rid of.

Right.

And even vancomycin, which we used to call our antibiotic of last resort, is facing resistance now too.

It highlights this ongoing challenge, this arms race, but also maybe the immense potential that still lies hidden in the vast, largely unexplored fungal kingdom.

Absolutely.

It's a powerful reminder that while fungi can heal,

nature is always adapting.

We have to keep looking.

Okay.

So moving from fighting infection to preventing organ rejection.

Let's explore another incredible fungal discovery, cyclosporine.

This story starts with the Swiss pharmaceutical company Sandoz, right?

There are people who are collecting soil samples from around the world,

standard practice, looking for new compounds.

Exactly.

And in 1970, a soil sample from Norway yielded a culture of tolipoclatium inflatum, which we now call tolipoclatium nivium.

Researchers found it produced a novel cycle peptide that's a circular chain of amino acids, and it had some interesting anti -fungal activity.

But crucially, an initial extract from its mycelium, that's the vegetative sort of thread -like part of the fungus, showed unusually low toxicity to animal cells.

Ah, okay.

That's key.

That was a critical finding.

Because often, potent compounds are also pretty toxic to our own cells.

So this low toxicity immediately flagged it for more investigation.

Right.

So because it wasn't toxic, they could test it for other things, like cytostatic, antiviral, immunosuppressive properties.

Precisely.

And what they found was, well, truly groundbreaking.

It was strongly yet selectively immunosuppressive.

Selectively.

What makes that so remarkable?

Well, it inhibited the multiplication of specific immune cells called lymphocytes, particularly the T helper cells, without affecting other rapidly dividing body cells, like those in your bone marrow or your intestine.

It was completely unlike earlier drugs.

Okay.

So the older immunosuppressants were more like a blunt instrument.

You could say that.

They often worked by broadly blocking cell division, mitosis in all cells, which, yes, prevented organ rejection, but it caused severe, really debilitating side effects, things like diarrhea, anemia, because they were messing with normal cell replacement in tissues that divide quickly.

Right.

Makes sense.

Cyclosporine was different.

Its effect on lymphocytes was reversible, and it wasn't toxic to them.

It seemed to have no serious side effects in mammals, which made it incredibly promising for humans.

So Sandoz had this revolutionary discovery on their hands, but then they hit a major hurdle.

It would cost something like $250 million to develop the drug and get it approved by the FDA and the U .S.

Right.

Huge sum.

And the market for organ transplantation back then was considered pretty small, especially given how poorly earlier immunosuppressants had performed.

Management actually considered just dropping the project.

Yeah.

It's a fascinating glimpse into how drug development works, isn't it?

And it begs the question, how was it saved?

How did it avoid the scrap heap?

Well, luckily, cyclosporine also proved effective against rheumatoid arthritis.

That's a condition with chronic immune -mediated inflammation.

Ah, a bigger market potentially.

Exactly.

And treating rheumatoid arthritis was an approved research goal at Sandoz.

So that provided a new pathway, a justification for the drug's development.

So kind of serendipitously, cyclosporine was saved from being tossed into the trash heap of biochemical history.

Amazing.

And by 1976, they'd figured out its complex structure.

An 11 -amino acid cyclopeptide with one amino acid they hadn't even seen before.

That's right.

I -aminobutyric acid.

And while tolipoclidium nivium actually makes at least 25 different cyclosporines, all with 11 amino acids, cyclosporine A turned out to be the most pharmacologically active one.

That's the one we simply know as cyclosporine today.

Its discovery was just a testament to the incredible targeted power you can find in fungal compounds.

Its impact has been just immense.

Oh, absolutely.

Once it was in widespread clinical use, they did notice some kidney damage initially.

But that's now minimized or avoided by using lower doses alongside a steroid, prednisone.

Patients do have to take it indefinitely to maintain the effect.

But still, because of how selective it is, cyclosporine is undoubtedly the best immunosuppressant discovered so far.

It's the treatment of choice after almost all organ transplants.

By 1996, over 200 ,000 transplant recipients were using it daily.

That number is surely much, much higher now.

And its potential for treating a whole range of autoimmune diseases, juvenile diabetes, multiple sclerosis, rheumatoid arthritis that's still being actively explored.

And interestingly, that fungus, tolipocladeum nivium, it's actually the anamorph, the asexual reproductive stage of a different fungus called cordyceps subsessilis.

Fungal life cycles can be complicated.

So fungi clearly have this incredible life -saving power.

But their role as nature's engineers doesn't stop there, does it?

Yeah.

Let's pivot a bit.

How is their biochemical prowess being used to make our everyday world better, transforming industries from, say, food to even fashion?

Absolutely.

Fungi are truly incredible chemical factories.

They produce this vast array of useful metabolites for industrial and food applications.

Take citric acid, for instance, produced industrially by aspergillus niger.

You find it everywhere.

In foods, soft drinks, cosmetics, even in leather manufacture.

It's ubiquitous.

The same fungus, aspergillus niger, also produces gluconic acid, which you find in some foods and cleaning agents.

Aspergillus terraeus gives us idaconic acid, used for making acrylic resins.

Rhizopus nigricans produces fumaric acid, used in wetting agents.

We even get riboflavin, which is vitamin B2, a vitamin supplement, from armothacium ashby, and gibberellic acid, a really potent plant growth hormone from Fusarium maniliform.

That's an impressive biochemical arsenal.

It's almost like fungi have their own universal toolkit they can deploy.

Yeah.

What about enzymes?

You mentioned those earlier.

Fungi never really secrete these proteins to digest food or dissolve through things.

How we harness those industrially?

Oh, we've harnessed a whole suite of them.

Amylases, for example, they hydrolyze starch,

breaking it down into simpler sugars.

We use them in adhesives and also to clarify fruit juices, making them clearer.

Invertase breaks down sucrose, table sugar, and that's essential in candy making to stop it from crystallizing.

Also used in making non -crystallizing syrups.

Proteases, those are actually mixtures of enzymes that break down proteins they find uses in softening leather, clarifying beer, and as really powerful stain removers in laundry detergents.

Ah, the biological washing powders.

Exactly.

Pectinase clarifies fruit juices too, and it helps in flax redding, which is a process for making linen.

Lipase, often from rhizopus, can improve food flavor and definitely boost detergent cleaning action on fatty stains.

And then there's glucose from aspergillus and penicillium.

Used to remove glucose from eggs before drying them, remove oxygen from canned foods to preserve them, and it's even used in diabetic test papers.

And maybe one that's familiar to quite a few listeners,

alpha galactosidase.

Also from aspergillus niger.

Isn't that the active ingredient in products like Bino?

The stuff that helps prevent flatulence if you eat beans or cabbage?

That's the one.

For people who struggle to digest food, this enzyme breaks those sugars down before gut bacteria can get to them and ferment them, which is what causes the gas.

It's remarkable, isn't it?

How a fungus' simple need to digest its food has unlocked such a diverse industrial toolkit for us.

Okay, now for some really unexpected places fungi are making a difference.

We usually think of fungi as needing oxygen to survive, being primarily aerobic, right?

But nature always seems to have exceptions.

It certainly does.

I confess I taught that fungi were aerobic for many years myself.

But back in 1975, Dr.

Orpin discovered these obligately anaerobic chytridiomycete -like fungi.

They were living in the room in the digestive system of herbivorous mammals like cows and sheep.

Anaerobic fungi.

Living without oxygen.

Exactly.

A unique type of single -celled fungi thriving only in oxygen -free environments.

By 1994, they described about 15 species, mostly in the genus neocalomastics.

That's fascinating.

So they've adapted to live without oxygen.

What does this mean for us, practically?

Well, they have unique features.

No mitochondria, which are usually the powerhouses of cells.

Often they have multiflagellate zoospores swimming reproductive cells with multiple tails.

But crucially, their rhizomycelia, their sort of root -like structures,

are incredibly efficient at penetrating plant material and breaking it down.

Better than our usual methods.

They possess enzymes that break down cellulose, the tough stuff in plants, even more effectively than some of the standard industrial celluloses we use.

And molecular studies even suggest these fungi might have acquired these super -potent enzymes through something called lateral gene transfer from bacteria.

Like, they borrowed useful genes from a different kingdom altogether.

Nature mixing and matching.

Exactly.

And this discovery naturally leads you to wonder.

Given the hundreds of different ruminant species on Earth,

how many more unique and useful rumen fungi might be out there?

Maybe with completely novel enzymes, it's another really powerful reason to value biodiversity.

Maybe even saving endangered species like the rhinoceros is important not just for the animal, but for the unique microbes living inside it.

A hidden world within a world.

Right.

And these unique fungi, they're now placed in their own distinct phylum, the neocolomastigo mycota.

Beyond their natural abilities, fungi are also proving to be incredible biological factories for exogenous gene products.

That means making proteins from genes that come from other organisms, right?

That's right.

And because fungi are eukaryotes, like us, they're actually much more suitable than bacteria for incorporating and expressing genes from other eukaryotes, including humans.

Why is that?

Well, they handle the complex protein folding and modifications often needed for eukaryotic proteins much better than bacteria typically do.

If you look into the scientific literature, you'll find loads of examples now.

Fungi can be genetically transformed, basically engineered, to act as hosts for venters carrying multiple copies of genes from other organisms.

They've already been persuaded to express and secrete a whole range of human and other eukaryotic gene products.

Things like insulin, human growth factor, human tissue plasminogen activator, that's a clot -busting drug.

Even bovine chymosin, the enzyme used in cheese making, plus industrial enzymes like amylase and cellulase, the potential for medicine in industry is just vast.

And thinking about these complex compounds fungi make naturally, it reminds me artists are also tapping into fungi, aren't they?

I heard of mycologists using fungal pigment to dye natural fibers.

What's the story there?

It's all about the diversity of their natural pigments.

It's quite amazing.

For example, a friend of mine, mycologist Luna Cheska, she actually knitted a wool vest using standard commercial white wool, but she dyed it herself using compounds extracted from 16 different species of fungi things like

It's a beautiful example of fungi's natural chemical palette being applied in a really creative way.

What's fascinating here is just the sheer diversity of applications, from life -saving drugs to art.

But maybe one of the most pressing areas now is environmental remediation.

Cleaning up our messes.

I heard students at Yale discovered a fungus that can break down plastic.

That's right.

Pestilotiopsis microspera.

It's a type of coelomycetus anamorph basically, a group of fungi that reproduces asexually using specific structures.

And yes, it can break down polyurethane.

So the search is definitely on now for fungi that can tackle other really stubborn plastics like styrofoam.

Which would be huge.

Absolutely.

Given the mountains of plastic waste in landfills and sadly in our oceans, plastic that just sits there for centuries without much apparent degradation, finding microorganisms that can actually decompose it.

That's an infinitely worthwhile endeavor.

We simply have to pursue it.

And extending that idea of using the fungus itself.

Fungi are literally shaping our future materials, aren't they?

Yes.

Since around 2010, people have been using fungal mycelium, the vegetative part, to grow things.

Yes, exactly.

Using the ability of mycelium to grow into and fill any shape of space it's given.

It's being used to generate completely new types of products.

Imagine literally growing your packaging instead of molding plastic out of petroleum.

That's a total paradigm shift in material science.

So how does that work?

How do you grow packaging?

Well, the fungal mycelium is grown inside a mold, a template of the shape you want.

It's fed on readily available agricultural stuff like waste cotton holes or wood fiber.

And in just five to ten days, it grows and fills the mold, taking on the desired shape.

Companies like Dell Inc.

are planning to cut millions of pounds.

They estimate 20 million pounds a year of non -negating packaging by switching to this fungal foam.

Wow.

And it has the huge advantage of being readily compostable.

It just breaks down naturally, returning cleanly to the environment.

That's fantastic.

And it's not just packaging.

No.

Car manufacturers, like Ford, are even starting to replace some petroleum -based plastic parts in vehicles with this fungus -based foam.

We're talking about replacing maybe 14 kilograms, about 30 pounds, of plastic per car.

And since they make thousands of cars a day, that adds up to significant weight savings, which helps fuel efficiency and vastly improved biodegradability at the end of the car's life.

People are even using fungal mycelium to make furniture and lampshades.

It's really taking off.

So when we pull all this together,

what does this all mean for us?

I mean, from the accidental discovery of penicillin saving millions,

to the targeted development of cyclosporine revolutionizing transplants, to the everyday enzymes making our food and detergents better, and now this innovative use of fungal mycelium for eco -friendly packaging in car parts.

The story of feng shui is just one of incredible, and I think often really underestimated, potential.

It's a powerful reminder, isn't it?

That some of those profound solutions to our biggest challenges, from health to sustainability, might just be growing right under our noses, or maybe deep inside a rainforest leaf, just waiting for us to find them.

That really is the ultimate takeaway, I think.

We've only identified and named maybe 5 % to 10 % of the estimated 1 .5 million fungi species thought to exist on Earth, and far, far fewer have been properly examined for their pharmaceutical or industrial potential.

We've barely scratched the surface.

So much more to discover.

Exactly.

It strongly suggests we can probably count on the fungi for quite a few more pleasant surprises in the decades or even centuries to come.

Imagine, for example, finding a fungus from an African rainforest that produces a compound mimicking insulin.

That could completely transform diabetes treatment.

It just highlights this vast frontier of discovery that still awaits us within what we call the fifth kingdom.

It's a constant invitation to be curious and keep exploring.

We really hope this deep dive has given you a newfound appreciation for the incredible, diverse, and often really surprising world of fungi.

Thank you so much for joining us on the deep dive.

On behalf of our whole team here at the deep dive and last -minute lecture, we appreciate you tuning in.

We'll see you next time for another exploration into what makes our world tick.