Interview by Dennis Walker

Dr. D Marshall Porterfield has spent roughly three decades thinking about one of the biggest problems facing humanity’s expansion beyond Earth: how do you keep humans alive when the biological systems we take for granted on this planet are no longer readily available?

A professor of Space Biology and Biophysics at Purdue University with a background at NASA, Porterfield makes a strong case for the largely untapped potential of fungi innovation to support humans in space travel and interplanetary development.

Porterfield’s research explores what he describes as mycoponics— systems designed to grow and study mycelial organisms in controlled environments and which he is pushing forward through the company MyCo that he founded—and their potential applications ranging from regenerative life support and biopharmaceuticals to advanced materials, biosensing and even biological computing.

I spoke with Porterfield about why fungi may be essential to long-term human habitation beyond Earth, what his laboratory is discovering about previously invisible fungal structures, and why mycelium could eventually become something much more than a source of mushrooms.

Marshall Porterfield: I’ve been really interested in biology and life support for the major portion of my academic career. I originally thought I was going to do biomedical illustration, but once I got into chemistry and physics, I realized that was really where I needed to be.

I started thinking about what would be required for humans to do the next level of missions beyond what we’ve already accomplished.

We got out on the Moon, then pulled back into low-Earth orbit and started doing the same thing over and over again. We’re not really making progress.

The limiting technology for humans to leave Earth isn’t necessarily rockets. It’s biological.

That’s really what I’ve been focused on for 30 years.

Porterfield: When we were developing controlled-environment agriculture, we were focused heavily on production—how do you grow plants without soil?

But one of the biggest gaps is actually on the recycling side.

How do you get those materials back into starting substrates for growing plants again? How do you recover mineral nutrients and upcycle them into valuable things that plants can’t produce?

When you look at the ecosystem approach required to support humans in space, that’s all fungi.

Everything fungi do for us on Earth has to be engineered into a regenerative system so they can perform those same services for us.

Every nutrient has to be recycled over and over again. Water is going to pass through plants and humans hundreds of thousands of times in one of these systems.

Fungi are going to be at that limiting step. They’re going to break the logjams in regenerative technologies.

We need the recyclers. And that’s actually where there is the least amount of research and the least amount known right now.

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Porterfield: We started looking at the mycoponics system as an interface for growing and producing mycelium under optimal conditions.

What we’ve been able to observe are structures and tissues that normally would never have been observable.

We’ve actually seen what appears to be a reproductive digestive organ equivalent to the mushroom, but occurring in the soil. It produces a nodule that looks like a fruiting nodule, and then it develops structures that drive downward like a root system and branch out.

We believe this is the foundation of a specialized excavation system in fungal biology.

That has enormous implications for pharmaceutical manufacturing because so many pharmaceuticals are produced through mycelial systems.

Traditional liquid-culture systems are limited by oxygen and transport. We’ve overcome some of those limitations with mycoponics and have been able to maintain mycelial cultures in a hybrid liquid-solid state for more than a year.

That gives us a manufacturing platform where we can produce the fruiting body, the mycelium and the exudate separately, then identify and measure what molecules are being produced, where, when and how.

Porterfield: Absolutely. One of the things I want to do with psilocybin is recover the exudate from the mycelium so we can grow the organism completely and produce medical-grade material while separately examining the mushrooms, mycelium and exudate.

We can sample all those tissues and determine which compounds are where.

And the pharmaceutical applications are only one part of it. We’re also looking at materials, food and green chemistry.

We can grow three-dimensional mycelial materials and potentially produce structures in different shapes. We can grow aerial mycelium from liquid culture onto a solid substrate de novo.

It becomes a continuous bioproduction system.

Imagine something almost like a tube continuously producing mycelium as you feed it liquid media.

Porterfield: Over the last six months we started integrating extracellular electrodes into the mycoponics systems.

It’s actually a perfect vehicle for electrophysiology because we don’t have to stick an electrode into the tissue.

We put the electrodes onto the tubes and the mycelium grows with the electrodes. Some of these systems are now a year old.

We can literally look at their EEGs—what we call mycelial EEG—and expose them to different light and chemical inputs.

We’ve already completed a baseline study using 15 different physicochemical inputs, including light and chemicals, and we can discriminate what they’re sensing from those inputs.

Porterfield: I think it does.

If we can integrate electrodes into a mycoponics tube containing growing mycelium, you have a completely living sensing organism and a pathway to communicate with that organism through its electrophysiological activity.

We’re now able to make tubes a meter long.

If I can put a million electrodes on a meter-long tube, I think we’re going to be able to do biological computing using that as a computing platform.

I think we ought to be able to develop AI computing through the mycelium on a neuromorphic computing platform.

Porterfield: If these mycelial networks really are connected at the continental level, which is what we think they may be, we want to put a mycoponics system with integrated electrophysiology into the field and let it connect.

Imagine having one system on one coast and another on the other coast, with an electrical connection through the internet.

We could try sending coded messages through the mycelial network and determine whether there’s an alternative communication network available through these organisms.

That’s what we’re going to be trying to do.

Porterfield: Fungi are going to play a really important role.

We’re learning that mycelial systems have an enormous influence on soil ecosystems, much of which is hidden beneath the soil surface.

With mycoponics, we can begin to dissect those systems and actually see what they’re doing.

We’re seeing fungi controlling water at the soil level and mediating how plants acquire water and nutrients.

When you think about the role fungi may have played in the original colonization of land on Earth, it makes sense that they could potentially perform similar functions in creating biological conditions for colonizing and terraforming other planets.

And there’s another interesting possibility.

The carbonaceous asteroids we’re studying contain organic molecules that could potentially serve as substrates for fungi.

The components of life are already present throughout the universe. We’re not necessarily starting with just carbon dioxide, nitrate and ammonia. There’s already a complex primal soup there—a product of the universe.

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Porterfield: One of the things we’re looking at is taking human waste streams, converting them into materials, combining them with regolith and actually printing infrastructure.

We could potentially print mycoponics components from deep-space materials and human waste streams.

We could use materials that exist on the Moon to print the infrastructure required for agriculture.

Those are going to be critical capabilities for enabling long-term human presence in these environments.

We also need to think about pharmaceuticals.

How do you create a pharmacy for an entire crew when you don’t know what they’re going to get sick with before they leave?

Personalized medicine may require different drugs for different individuals. We ought to be able to maintain a library of mycelial drugs specialized for an individual based on their genome, then activate the appropriate culture and produce the drug on demand in space.

That’s going to be critical for stabilizing human exploration in that domain.

Porterfield: The foundational potential of mycoponics is that we could open up the world of mycology in a way that has never been possible before.

Hydroponics transformed our ability to understand and work with plant systems. Mycoponics could do something similar for fungi.

We ought to be able to formulate specific media for different types of fungi, including mycorrhizal fungi and previously uncultured fungi that we haven’t been able to domesticate.

That’s how you open up the world of mycology: by allowing the entire domain to contribute, rather than just a few cultivated species.

And once that happens, I think there will be waves of new technology.

Green biomanufacturing, the chemical industry, energy systems, agriculture and agrochemicals—all of these could potentially be transformed by using the foundation of mycology and everything these life systems can bring to engineered systems.

We’re in the earliest part of the biological century.

Ultimately, we’re going to have to learn how to work with all the organisms of the planet in a collaborative manner.

That’s where I see the potential for our future growth.

This interview has been edited for length and clarity.

Listen to the full interview with D. Marshall Porterfield on today’s episode of Mycopreneur Podcast