Nitrogen, but make it alive
For a hundred years, the way you fed a field was to build an enormous, energy-hungry factory, squeeze nitrogen out of the air at high heat and pressure, ship it in trucks, and pour it on the soil. Harrison Yoon runs a company built on a different idea: skip the factory. Let a microbe do the job, right where the roots are.
That company is Kula Bio, and as of November 2025 Yoon is its Chief Executive Officer. He had been President and Chief Operating Officer since 2020 - the operator who quietly turned a Harvard science project into something a farmer in the Midwest could actually buy. When founding CEO Bill Brady moved to Executive Chairman, Yoon stepped into the top seat the same week the company finalized its Series A-1 funding round.
The product Kula Bio sells is, technically, a bacterium. Its name is Xanthobacter autotrophicus - a mouthful that does something elegant. Most nitrogen-fixing microbes are lazy or finicky; they fix a little nitrogen, then quit. Kula Bio's trick is to feed the microbe a carbon-rich energy source first, so it stores up internal reserves like a camel storing water. Loaded with energy, the bug keeps fixing nitrogen from the air long after it lands in the soil, delivering it in the root zone exactly where and when the crop needs it.
The company's own shorthand for this is the best summary of Yoon's job: "moving the factory to your field."
The science started as a leaf
The origin story isn't agricultural at all. More than a decade ago, Harvard chemist Dan Nocera built what he called a "bionic leaf" - a system that used electricity, water, carbon dioxide, and engineered microbes to spin sunlight into liquid biofuel. The biofuel ambition didn't conquer the world. But the underlying insight - that you could energize microbes to do industrial chemistry - found a second life. Pointed at nitrogen instead of fuel, it became Kula Bio.
Turning that elegant lab demonstration into jugs of product on a distributor's shelf is a different sport entirely. It is a problem of fermentation tanks, shelf life, cost per acre, and farmer trust. Which is precisely why the board handed the company to a fermentation lifer.
A career measured in tanks
Yoon trained as a chemical engineer, earning a Ph.D. in the field and completing postdoctoral research at Cornell University's College of Engineering. What followed was more than 25 years of work that spanned the U.S., Europe, and Asia, all circling the same craft: cell culture, microbial fermentation, and bioprocess engineering. He is the kind of person who understands a microbe as a manufacturing line.
Before Kula Bio, he was at Agrinos - a microbial crop-nutrition company later acquired by American Vanguard Corporation - where he served as Chief Product Development Officer and then Chief Production and Operations Officer. There, he oversaw global R&D and pushed microbial biostimulants from the lab into commercial reality across multiple international sites. It was, in effect, a rehearsal for Kula Bio: take biology that works in a flask and make it work on a continent.
His curiosity isn't confined to row crops. Yoon has also been involved with California Cultured, a venture applying plant cell-culture expertise to grow cocoa ingredients for chocolate without the cocoa tree. The throughline across fertilizer and chocolate is the same: take a living cell, understand exactly what it needs, and convince it to produce something useful at scale.
Why this matters now
Synthetic nitrogen fertilizer is one of the great inventions of the modern era and one of its largest emissions problems. Making it is energy-intensive; overusing it leaches into waterways and releases potent greenhouse gases. A biological alternative that is cost-competitive - not a charity purchase, but a real economic choice - is the holy grail of regenerative agriculture. Kula Bio's pitch is that supercharged microbes plus precision application can hit that mark.
Under Yoon, the company has pushed toward the least glamorous but most important milestone in biology-as-a-product: shelf stability. Living things are hard to bottle. Kula Bio's launch of shelf-stable nitrogen-fixing products - branded Kula-NSP and Kula-NextSP - is the kind of unsexy breakthrough that decides whether a technology stays in a lab or ends up in a barn.
With more than 25 farmers already buying product and a fresh round of capital behind him, Yoon's mandate is clear and brutally concrete: prove the biology in the field, again and again, season after season, until a microbe in a jug is just how farming gets done. The science is done being clever. Now it has to be reliable.
That's the quiet ambition behind the man and the bug. Not to invent nitrogen fixation - nature did that. To make it scale.