From Microbiome to Macrobiome: Exploring Humanity’s Greatest Frontiers

10/17/24   |   Written by Homeworld Collective

An interview with Braden Tierney, PhD

Braden Tierney is the co-founder and executive director of the Two Frontiers Project. The Two Frontiers Project leverages and explores life’s diversity and humanity’s greatest frontiers, the oceans and space. In this episode of the Climate Biotech Podcast, you’ll hear about how a very creative biologist combines his unique set of skills to translate his training from the microbiome in humans to the macrobiome in ecosystems.

Listen to the full conversation on Spotify or Apple Podcasts, or read on for snippets from the episode (lightly edited for clarity).

Headshot photo of Braden Tierney
Photo credit: Braden Tierney

How did you first fall in love with science?

I grew up in the Boston area as you can tell from my schooling. I’ve spent a lot of time exploring Boston, and we have incredible scientific horsepower and institutions here. We’re also surrounded by pretty amazing nature that’s not too far off. Being here and getting to fish and dive and really explore, as well as being surrounded by great microbiologists and scientists from a very young age — that turned me into the person and the strange scientist that I am today.

None of my family’s in science, but I just kind of knew from when I was really little that I wanted to study science. I thought that being paid to think about the hardest questions humanity has ever faced is the coolest job in the world, and getting to work with other people who are equally excited about it is even cooler.

When I was a kid, I read this book called Shadow Divers by a guy named John Shatterton. It scared the hell out of me. I was in, like, 6th grade. It’s where I learned about the bends, and about all the awful things that can go wrong when you start scuba diving.

I read that and thought, I’m never doing that — ever, ever, ever. But then a few years later, I had a chance to do a little sample dive and immediately fell in love with it. I thought, it’s worth the risk. From then on I dove every opportunity I could, and I had this dream of, okay, maybe there’s a way to incorporate being in nature and exploration with my work someday.

When I started my PhD — you can ask my friends about this — I was saying I want to commit intellectual arbitrage between medical and environmental science. Medical science gets all the money, so if you can build a reputation and learn the incredible depth of techniques that are being applied there, you can have an outsized impact in environmental sciences if you move them over very quickly. 

I generally believe that you should learn a trade instead of following a passion — or learn a trade first, then follow a passion. For me, it was diving, data science, and microbiology. And then, when you combine your trades, it creates a unique skill set with which to do unique work. 

Microbes are self-assembling machines

There’s one underlying thesis that links together every single thing I have ever done: microbes, in general, are nature’s self-assembling machines. They have been evolving for billions of years.

We as humans have this tendency to anthropomorphize microbes. When we want to study them in a human context, we call it the human microbiome. When we’re going to study them in the deep ocean, it’s an ocean vent microbiome.  

Except maybe, in fact, the microbe — the machine — is ubiquitous. Maybe the tools they use to survive in those environments — their genes and proteins and metabolites and the evolutionary mechanisms that allow them to survive — they’re all the same. 

I’ve worked in a bunch of fields that sound very disparate, but they’re united by this idea of microbes being ubiquitous, self-assembling machines that can modulate their ecosystems. 

What’s the Two Frontiers Project?

The Two Frontiers Project is what I call a micro-institute — we’re a nonprofit research organization with a small team, but we’re able to apply for grants in a similar way to a university or an academic institute. We’re dedicated to exploring life’s diversity in extreme environments, with an emphasis on humanity’s greatest frontiers, the oceans and space. 

What’s really interesting about those two environments in particular is that life’s adaptations to overcome the adversity of living in such places — especially those of microbes when in places you wouldn’t expect them to survive — are always interesting and often useful.

For example, a microbe that lives in a vent with a lot of carbon dioxide — which we’ll talk about — is likely to be capable of feeding off of that carbon dioxide to a certain degree. Exploring humanity’s greatest frontiers enables us to do work that is both important for survival in those frontiers, and also for learning a lot of really cool stuff about preserving them moving forward.

Photo credit: Two Frontiers Project

Finding a carbon-capturing microbe in shallow seeps

We need self-assembling machines that can remove CO2 from diverse environments. We’re going to go to [marine] seeps which were shallow enough to be exposed to sunlight, which is really rare among the world and not well-studied relative to other seeps, especially microbiologically speaking. Sunlight means you’re likely going to have phototropes, microbes that live off CO2 and sunlight, kind of like plants do.

We scraped together enough cash — barely — to go and do this sampling expedition. It was an incredible amount of effort to get them. 

There’s a data aspect. There’s a physical sampling aspect. All the sampling needs to be safe. You need all the right equipment. You need to be able to measure the geochemistry. It has to be fast — and we’re doing this in a hotel room, right? So we had to have everything be hyper-deployable. Now, all of our kits pack into Pelican cases — briefcases that we can drop-ship and take around the world.

And we got the microbes. Within two months, Max Schubert pulled out an isolate that was extraordinary in terms of its characteristics to capture carbon or sequester carbon. That kicked off this ridiculous amount of momentum where we were able to raise more money for our carbon initiatives. 

We started a coral initiative for sampling corals around the ocean, working on reef bleaching and climate change impacts on reefs. We started building a single platform for using geochemistry to identify culture and conditions, to identify microbes that were useful for everything from methane capture to carbon dioxide. We started building out a living database, which sequences every sample we take. Every microbe. We take everything we culture and then bank those samples so we can share them with the community.

What’s so special about Cyanobacterium aponinum?

We have this really promising, novel strain of an organism called Cyanobacterium aponinum. What’s special about this bug is it grows very quickly in high CO2. We estimated a doubling time of about 2.5 hours, which is very fast without much optimization. And more interesting than the growth rate is that, universally, this bug grows to extremely high dense biomass, which then sinks.

Cyanobacterium aponinum grows fast, and it makes biomass that sinks. But when you compare it to other similar species and strains, they don’t sink. 

When this fast-growing organism sinks to the bottom of whatever it’s growing in, it’s sequestering carbon, and it produces about 22% more biomass compared to other strains. 

I find the sinking aspect really cool. There are so many directions you can take this — for example, we could start putting it in raceway ponds and seeing how quickly it can sequester carbon. But the most immediate step is building tools for engineering it so you can have it produce something that’s useful — like a carbon to value setting, like sugars or oils.

A lot of the questions that immediately hook me sound very basic and removed from physics and climate change. But if we can figure out what machinery makes a cell sink quickly, suddenly this one application can translate. 

Let’s say you had a strain that could produce bioplastic to make new water bottles, but you’re having a hard time concentrating the resulting bioplastic. It’s all just floating around and you’re not able to actually easily sink it and get it into one place to make a water bottle. Well, if you knew the genetic machinery for making a microbe sink quickly, suddenly you can concentrate that biomass very, very easily. This kind of trait that comes from nature can be applied to all kinds of existing bioengineering solutions — if you can crack the biology behind it.

"There's one underlying thesis that links together every single thing I have ever done: microbes, in general, are nature's self-assembling machines." – Dr. Braden Tierney, The Climate Biotech Podcast

Learn more about the Two Frontiers Project and stay in touch 

At the Two Frontiers Project, we’re always looking for mission aligned partners. We focus on building core technology to solve major problems. If you’re a funder who feels that academia is moving too slowly in the wrong direction and that biotech has yet to really develop cost-effective products; if you’re a scientist who wants to work on those core technologies, or you’re someone who wants to spin out something we’ve done into a company; I say reach out — you’re the kind of people I want to work with. 

We want to find people who are really aligned on this axis of doing science in a different and highly impactful way. People who have seen science fail, who are coming at it from a point of humility, and who are just excited and curious. Go to our website, ping me at braden@twofrontiers.org. I would absolutely love to chat with anyone who falls into those categories.

You can also find any data we’ve published or talked about publicly available. By the end of 2024 we’re going to have a portal on our own site — and that’ll have everything you need for accessing data, resources and projects and volunteer and ideas and donations and more.

By Homeworld Collective