When we talk about the path ahead for synthetic biology, from necessary tech breakthroughs to ambitious policy changes, there is a reason why we call it building the future. Futures don’t manifest in a blink. Scientific understanding inches forward; our capacity to produce with it multiplies. The towers of technology built tomorrow will stand atop materials that exist today.
To Rachel Armstrong, that material can be abstract—like the incremental knowledge that lets us understand and manipulate carbon sequestering microbes—but it can also be concrete, like the soils beneath our cities, wood, fungi and established building materials like, well, concrete. Armstrong is a professor of regenerative architecture at KU Leuven in Belgium and senior TED fellow. Her research on next generation sustainability focuses on the networks connecting humans, our technology, the planet, and the creatures that live alongside us.
“Net zero is not enough,” Armstrong says when imagining the city of the future. “A building itself must have a positive impact on the environment. They could be carbon negative buildings, or it could be promoting life and biodiversity. It could be about social cohesion, or ecosystem restoration.”
Armstrong began her career in medicine. In the 1990s, she spent a sabbatical with a hand surgeon at a leprosy colony in Pune, India. Armstrong was struck by the ways that the residents, suffering from skin lesions and nerve damage, adapted with devices like leather straps and wax molds, and built a strong community. “I saw how very simple interventions into the body really helped transform people’s lives,” she says. “They not only could live their daily lives, but they could restore their social function.”
That work compelled her to study experimental architecture, and the interface between technology, bodies, and habitats by prototyping new possible relationships between them. Since then, Armstrong has become a visionary voice for how we can use microbes to build a sustainable future. “How can materials actually act as if they are living?” Armstrong asks. “How does design become nature?
GROW recently spoke with Armstrong about her work and the bold ideas we need to live our best lives on this planet. The conversation has been lightly edited for clarity.
Grow: How did you see your vision for living or regenerative architecture coinciding with biomimicry, which was already gaining popularity by then?
Armstrong: Biomimicry was about copying biological form inspired by living organisms and then realizing them with existing materials such as steel and concrete. Forms are very interesting, but the impacts were the same as modern buildings, so I was trying to think of how we actually get life and nature—the only systems that we know—to reverse environmental impacts from the trajectory of modernity. The goal was to create systems that really engaged with nature as a process and not just a form.
How did that shape your vision for what you call living or regenerative architecture?
This group of living technologies that were coming out of biotechnology, computer sciences, were really challenging our definitions of life. For me, living architecture was the application of living technologies and living materials into our living spaces and habitats. When you had entities that were living, maybe not alive, because they didn’t have the standard definitions of life that were carried with them, we started to get this blending of material and technology.
What does that look like in practice to, as you say, blend innovative materials, processes, and forms?
We can use materials, as in mycelium biocomposites, for example to grow our surfaces and structures, if we leave them living so that they continue to adapt and respond to environments. It’s most interesting to me when you keep the microbes living.
If we think about fossil fuels, they are literally fossilized microbes and other organic matter that has been pressurized and transformed into a dense energy source. But you know when microbes in soils and other biological substrates are out and running around, native in the living world, they actually have a much broader range of metabolisms. If we really tap into a biotechnology of metabolism through microbes, that gets us to things like the microbial fuel cells that I work with, thanks to bacteria and other microorganisms that remediate local environments by processing toxins and in doing so, also generate energy. And so at the moment, I’ve got a real love and focus for microbes that make bioelectricity.
So this vision for architecture relies on exploiting unique powers of microbes and natural metabolism.
Yes, you actually get a combined platform for very interesting stuff. They metabolize your waste, and they “poop” electrons, essentially. They can also be used as a source of transformation in chemistry: You get biosynthesis that comes out of the excess electrons produced by microbial metabolism.
What makes that approach so unconventional?
In the traditional vision of modern infrastructure and utilities there’s a kind of singling out of the infrastructures of life to produce clean water or energy. But microbes, being at the base of the biosphere, can integrate all those things. If every single one of our homes had a little sewage plant, we could capture all our bioplastics. At the same time, we could remediate waste streams, and then recycle large parts of the waste matter and use them in different ways back in our buildings. It’s all about creating a circular infrastructure flow through the resources that we use in need every single day, while generating less carbon. Or, if we do generate carbon, it’s about the smart reuse of that carbon.
What progress have people made to this end?
You can think of the full picture of “living architecture” currently as the domestic scale circular infrastructure for turning the urine and gray water in homes into clean water, biomass production, bioelectricity, and bioremediation function. One example is “pee power.” The work of Ioannis Ieropoulos looks at pure urine streams as a way of putting pee to good use in public spaces, like in pop-up infrastructure to deal with climate emergencies, for example. When infrastructure goes down during a flood or wildfire, it would be able to generate enough electricity to keep your mobile phones charged, and even power an autonomous wi-fi system..
These are stepping stones towards achieving genuinely regenerative architectures. They provide the sanitation that’s necessary; they provide the energy that’s necessary; they provide biomass for new materials. And they provide the clean water and the treatment of sludge that can then go on to the land as fertilizer. So not just discarding waste, but actually allowing the microbes to process it to a point where their contributions become environmental enrichment.
And if we think of the pee power, as a basic unit, we can think about biotechnology that could lay different levels of engagement with the microbiome, within our bodies, buildings, and the local environment, and the biosynthesis that occurs in those microbial communities.
We can actually track the performance of these microbial systems by looking at real-time data streams which use the electrons produced by bioelectricity producing microbes. Julie Freeman, a data artist, has generated software that’s allowed us to see if the urine collection needs topping up or whether the microbes are behaving well. It’s a biodigital interface.
I think that biodigital can have quite a few meanings to different people. What does it mean in this context?
By “biodigital,” I mean the interface between the embodied microbes and electrons. I love electrons because they sit between the virtual and the classical realms. They allow biology to be weird. If we squeeze electrons through a tube, we start to get classical electronics. But when they’re in their rarefied form, in nature, they can have a quantum capacity. Biodigital is that strange space between us gathering electrons to try to read them in a classical context, while not beating the weirdness out of them.
Even though this is population scale averaging of your microbial electron transfer processes and the summation of these averaged out processes, it is giving us a snapshot into how a living thing is performing in real time.
So how does this type of architecture translate into more energy-smart or sustainable living?
It allows us to think about using energy smarter through microbes, and use less energy. Microbial fuel cells have been showing us how it would be possible through recycling your waste streams to live on a 12 volt electricity supply stored in a battery. To be able to design a house, or a lifestyle within an apartment, that could live entirely off a 12 volt supply is one way to greatly reduce the environmental footprint of our living spaces.
Just 12 volts?
That would be at the pinnacle of my dreams: to have our own energy that was powered by our own waste and the waste from our kitchens, and that we could still live a decent lifestyle. I think this is going to be possible as we get more types of low power electronics.
We’d make a huge dent in our carbon footprint, if we could go from 230 volts, which is about average for a Western apartment, to 12 volts. It’s always important to try to figure out how, by recycling and rethinking the tasks of everyday life, that we can really be smarter about the use of energy.
For me, the characteristic of modernity is that if you throw enough energy at something, you can innovate anything. This way of thinking implies that throwing energy at something is the solution.
How does this “throw energy at everything” approach stand out?
Nature has a weird materiality: it has systems and distributed processes. Nature does things in weak ways over time and space—these are not tactics that are associated with modern solutions, which are centralized, hierarchical and very, very powerful.
It’s not just about being inspired and informed by nature to create the solutions themselves, but rather looking to nature, the way it behaves to strategize better about how we use resources, how we relate to other bodies, how we regenerate our environments.
What work of that sort do you have going on now?
The project that I’ve got coming up is called microbial hydroponics. It’s about better connecting people and plants and waste and microbes. If you think about the way a forest works with its roots and microbial networks that help translate the regenerative chemistry in soils—how do we bring that dynamic into cities? How can we use what would normally be the underground transactions in a forest floor into the infrastructure or utilities of a home to enrich the productivity of our living spaces?
It’s not just about circulating carbon, but also about making lots of different things that you need. Almost like precision gardening using microbes as your tools. We can imagine artificial intelligence observing the electronic signals of microbes, which in turn relate to the chemistry of plant roots and the wavelengths of light, all of which are being powered by energy coming from the microbes powered by waste. There’s a lot of entanglements; it amounts to a much more ecosystemic design within our spaces, materials and buildings to create a better biodiverse network of exchange and ultimately may even do away with the concept of “waste.”
What examples come to mind of budding microbial technologies that move us toward that?
The mainstay of bioelectrical organisms in Microbial Fuel Cells that generate electrons are Shewanella and Geobacter that come naturally from in our organic waste streams. They’ve not been engineered yet. In the microbial hydroponics project, we are now starting to think about how we engineer those biofilms to create symbiotic communities of electroactive microorganisms, which may be the classical Shewanella and Geobacter, or we may also make communities with other types of microorganisms such as archaea or fungi. If they can work symbiotically with bacteria, then you can start to think about engineering the metabolisms to form communities that break down lignin and cellulose or generate the fundamental molecules for making bioplastics. They become like biofabrication units or tiny factories.
The biofilms that normally form would be complex and we’d need metagenomics for that. Since microbes are so small, we need a range of techniques for “seeing” what happens on their inside through their very versatile metabolism. With metagenomics, now we can get a population scale picture of which microbes are part of a community. But in the last 18 months, we’re starting to take parts of the biofilm community and starting to engineer it with very specific symbiosis in mind to create the first synthetic biofilms and start using synthetic biology tools.
This vision of home utilities appears to be drastically more decentralized than modern reality. What are the pros and cons of this decentralized scale?
For our living architecture project, we needed to engineer new metabolisms to deal with things like phosphate and noxious gases by engineering some microbes. We wondered whether—if any engineered microbes got out of our bioreactors—microbial fuel cells could mop them up. They could. Ioannis Ieropoulos and his team who specialize in the Microbial Fuel Cell technology saw that Hepatitis B got mopped up by the natural biofilm on the microbial fuel cell. It was a sign that these could be a sort of prosthetic immune system for our waste streams. This same framework, of bioremediating viruses present in waste streams, became very interesting considering the COVID pandemic.
We could now think of microbial biofilms as a kind of environmental immunology that could operate through your living space. To actually have a home-based environment where every citizen has an ability to clean up microplastics, viruses, and toxins that are just the byproducts from their everyday existence is very appealing.
So each person owns their contribution to environmental waste, in a sense.
Exactly. It’s a kind of citizenship, more than an economic contribution. It’s also an economics of the commons, rather than the economics of a private individual. It doesn’t easily fit within capitalism.
We’re never going to go head-to-head with the combustion of fossil fuels in terms of pound for pound energy that they provide. But for multitasking and creating healthy living spaces, microbial platforms are second-to-none. They have an inherent resilience, circularity and creativity that “dead” carbon just does not provide.
Can this vision coexist alongside capitalism? Where does centralization fit in?
When you’re talking about the living city of the future, there are some different politics, some different economics, different notions of living together. I don’t think regenerative architecture would necessarily be at odds with the idea that an individual might have private wealth or use the marketplace to obtain resources. It’s more about diversifying how we do things, and what kinds of value non-standard economies embody.This idea can coexist as a way for us to become active ecosystem members.
What I would like to see change is the level of excess and accumulation that has been made possible by burning fossil fuels and extracting things at an unprecedented scale. Maybe this is politically incorrect, but that may mean we’d no longer have billionaires. Even in the growth of a giant tree, there is a point where enough is enough, and it starts to distribute its nutrients through its roots in order to ensure a healthy community. And if you look at a chipmunk and how much it can stuff in its little face—there’s still a point at which that chipmunk stops. In a material world, it’s reasonable to expect limits to consumption.
There’s clearly no shortage of microbe-related ideas, especially within our world at Ginkgo. How do you see future urban design going even beyond that?
I think we’ll see our cities nested in the ground. I’m struck by the image of Cappadocia, the ancient underground city in Turkey. It’s partly carved out of the earth, and partly built above ground. Imagine rammed earth materials, domes that are earth based with simple clays as paints. Our cities could look much more like the ground that we inhabit, rather than gray and alien, as they do today. We will be using things like fiber optics of glass or bioplastics to transmit light down into the ground. The buildings will be warm without needing fossil fuels to heat them. Our biggest challenge will be ventilation and how we filter out dirty air. It’ll feel a little bit like living in a spaceship, but also like being nested within the earth that nourishes us.
How could microbes support the building materials in that vision?
The first thing I would say is that right now, there are no organic load bearing materials. Reinforced concrete is still the best bet for a skyscraper, for example; you don’t want it made of mycelium biocomposite. However, are skyscrapers still the buildings of the future? And there is a lot that you can do with biomaterials that’s structural but not load-bearing, like claddings and the facades.
What does that then look like beyond the home—perhaps in how the urban environment interacts with nature?
We’ve got a huge cleanup challenge. I think this is about making healthier cities for ourselves and our kids and the generations to come. Cities bear the scars of industrialization. These toxins and spoiled earths are in the ground for a very long time, so having an ability to restore and remediate them becomes an investment in the future of our soils, our water (which filters through the ground to be cleaned) and our cities.
We don’t really think of urban nature as being particularly healthy because it’s full of environmental pollutants from traffic and industry and building materials. If we think of regenerative spaces as being like fractionated soils—just as how the different fractions in crude oil perform different functions from wax to diesel—each different fractions can perform a different function within a modern life.
Soil is a complex material that is spatially organized. The organisms at the top of the soil like light and oxygen, whereas maybe two or three centimeters down, they start to become more anaerobic, their metabolisms change there. Each horizon has different functions and characteristics. The A horizon is essential for plant growth, as it contains a combination of minerals and organic matter. The B horizon contributes to nutrient storage and availability. The C horizon provides a source for minerals but is less directly involved in plant nutrition. By stratifying the different functions of soils, we can create the richness we need to build our living spaces, as well as to have healthy plants and create regenerative cycles needed for a robust ecosystem.
If you do this at the level of the community, your compost performs aerobic work at the top, anaerobic work at the bottom—you’re getting hydrogens and methanes and maybe building blocks for some bioplastics or other materials.
We can think of the soil as being a framework for an organic factory. But it’s not something that we can just take from, we also need to understand how we can nourish and take care of it, by living alongside and within it. We really stand a good chance in cities of having healthy nature and healthy environments, restoring our brownfield sites and the polluted land by better relating to our native soils, organisms and microbes—and figuring out exactly what roles we can play. I think that that is the groundwork for the city of the future.
Image Captions: 1. Protocells. Original photography by Rachel Armstrong, 2010. 2. Integrated bioreactor system. Courtesy of the Living Architecture project, 2019.
