Protein from Air? - An Interview with David McLellan from Jooules
This week, I had the pleasure of speaking with David McLellan, Founder and CEO of gas fermentation company Jooules. 🌱 Through my work as an advisor and these newsletters, I’ve been fortunate to connect with founders across various biomanufacturing technologies, but this was my first deep dive into gas-based fermentation — the process of making protein from air! 💨
David’s path to biomanufacturing was anything but linear. Growing up in New Zealand, he started out as a trainee forest ranger 🐾 and worked in the forestry and logging industry 🌲. But the appeal of a lifetime of physical labour faded, so David pivoted, earning an accounting degree and pursuing a career in finance. After nearly becoming a stock broker before the infamous Black Monday 📉, he navigated the finance world, from treasury finance in Wellington to Goldman Sachs in London.
When he eventually returned to New Zealand, a new opportunity awaited. The electricity market was about to launch ⚡, and David joined the newly formed “Contact Energy”. Following a number of years helping to shape the new sector David took his first step into entrepreneurship by establishing the Australian electricity futures contract and market, in partnership with the then Sydney Futures Exchange and NZ national grid operator Transpower.
“I didn’t make much of anything material from that experience, though it did transform the market!” 😅 David reflected, but he gained a lot of wisdom.
Alongside the derivatives business, David was also building a thermal processing company — a “canning” process, but without cans 🥫 — aiming to create shelf-stable food in pouches. This venture was his first introduction to capital raising. And while they successfully raised funds, he realized the real value was in the lessons learned. Here are David’s top three takeaways from that period:
Entrepreneurship isn’t easy. Don’t underestimate the comfort of a regular (professional) salary. 💸
Don’t reinvent the wheel. “We ended up with a museum of machinery because we tried to build everything from scratch.” 🛠️
It’s a journey, make sure you have the right team with you. Open, transparent communication with co-founders, employees, investors, and supporters is essential. 🤝
Following his own advice, David returned to the retail energy sector and then joined PwC as a management consultant. Yet, while he enjoyed the security, his passion for solving big challenges — like food security and climate change 🌍 — kept calling him back to entrepreneurship.
Looking at food security and emissions issues, David explored fermentation. While precision fermentation held promise, its reliance on crop-based feedstocks left it vulnerable to climate impacts. But gas fermentation was different: by using bacteria to convert gases like CO₂ and hydrogen into biomass, it offered a feedstock-free pathway.
“Is there a better way?” 🤔
Gas fermentation feeds bacteria with CO₂, hydrogen, and nitrogen, allowing them to grow rapidly, doubling in under an hour. This produces a “complete” protein rich in essential amino acids, making it a highly attractive ingredient. 🍽️
Jooules uses continuous fermentation to extract protein as it’s produced. The resulting biomass is collected, heat-treated (similar to pasteurizing milk 🥛), pelleted, and spray-dried, yielding a powder that’s over 75% protein. Since hydrogen production is energy-intensive, scaling gas fermentation will depend on access to cheap, renewable energy. ☀️
Founded in 2022, Jooules’ focus is B2B — providing high-quality protein ingredients for various food manufacturers. Currently, they operate at a 10L biorector scale, following a successful pre-seed round led by Sprout Agritech 🌿. Much of Jooules' research and development happens in collaboration with SCION, a New Zealand research institute with expertise in gas fermentation.
Building the right team has been one of David’s biggest challenges 👥**.** Being a sole founder can be lonely, so building a network and finding sounding boards has been invaluable. Another key challenge? Raising capital 💸. Deep-tech innovation is cash-intensive, and securing funds is never easy.
A standout principle for David is his commitment to paying people at or near market rate, rather than leaning solely on “sweat equity.” Striking a balance between salary and equity attracts the best talent and shows his commitment to building a robust team.
For David, the most rewarding part of entrepreneurship is the progress on tough problems and sharing wins with his team and supporters 🏆. Returning to that comfort of a regular salary isn’t on his radar anymore:
“People have stopped telling me to go and get a day job, as they know it’s not going to happen.”
As I do with every interview, I asked David if he had an ‘ask’ for the community. Jooules is currently raising a seed round to reach a 300L pilot scale. If you’re working in gas fermentation or exploring potential collaboration opportunities, especially in strain development or downstream products, David would love to connect.
