Row, Row, Row Your Molecule: Why 3-HP Finally Learned to Move

I was standing at the Institute for Sustainability, Energy, and Environment at the University of Illinois Urbana-Champaign a few months ago, giving a keynote. I came to Illinois more or less to see the corn — every year, we do a “harvest tour” to look at the changing face of American feedstocks and supply chain innovation. But my talk was not about America’s favorite bioenergy feedstock. It was to highlight that the bioeconomy has 5 Grand Challenges and they are interlinked. The bioeconomy doesn’t struggle for lack of ideas; it struggles when its parts refuse to move together.  How systems collapse when timing, interfaces, and incentives fall out of sync.

Months later, there more news out of the U of I, specifically from researchers at the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI). The news, around renewable 3-hydroxypropionic acid (3-HP), makes it clear that researchers are working at a system level now. Bravo! For years, the industry tried to row harder upstream:

• Higher yields
• More pathway optimization
• More genetic horsepower

Now, they’re looking downstream and speciafically to downstream processing costs, and to aspects of a 3-HP production system that deliver tight-spec, affordable molecules to customers. 

For more than two decades, 3-HP has been a perennial favorite of the bioeconomy. Named one of the Department of Energy’s original “Top 12” platform chemicals, it sits upstream of enormous markets: acrylic acid, superabsorbent polymers, coatings, adhesives, carbon fiber, ABS plastics. Diapers, paint, cars, toys. The demand has never been the problem.

“Row, row, row your boat,” the song goes, “gently down the stream.” Sung in a round, no less. Synchronization, not strength, is what keeps the boat moving. In 2025, 3-HP has finally learned the tune.

The Downstream Truth We Kept Avoiding

For years, the dominant narrative was that 3-HP couldn’t make it because biology wouldn’t behave. That story was convenient — and wrong. Companies like OPX Biotechnologies (later acquired by Cargill), working alongside Dow and Novozymes, demonstrated long ago that respectable titers and yields were achievable.

What refused to behave was downstream processing.

Neutral-pH fermentation created salts. Salts demanded acidulation. Acidulation produced gypsum. Gypsum produced waste, cost, and regulatory headaches. Dilute broths required energy-intensive evaporation and distillation. In many designs, downstream processing quietly consumed 40–60 percent of total production costs. The rowers were strong — but they weren’t rowing in time.

What’s different now is not a single breakthrough, but a synchronization across the system.

Recent work coming out of the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI) demonstrates high-titer 3-HP production using acid-tolerant yeast strains operating directly at low pH. That one design choice ripples outward: no neutralization, no gypsum, dramatically simpler separations. Adsorption and ion-exchange suddenly become viable. Water use drops. Energy intensity falls. Economics begin to behave.

The boat stops fighting the river.

Grand Challenge #3, Revisited: Building Survivors

This is where the third grand challenge from my ISEE talk becomes worth mentioning again: “Good policy doesn’t pick winners. It builds survivors.”

For renewable fuels, we often translate policy support into mandates and credits. For renewable chemicals, that translation breaks down. Molecules like 3-HP don’t tolerate volatility. They require long qualification cycles, tight specifications, and years of iterative learning between fermentation, separations, and end use.

Where government support truly mattered for 3-HP was not in the form of hand-outs, but a hand-up.

The Department of Energy didn’t try to subsidize a molecule. It funded CABBI as a Bioenergy Research Center — an institution deliberately designed to hold complexity long enough for real learning to occur. Stable, mission-driven support allowed researchers to abandon elegant ideas that scaled poorly, to prioritize acid tolerance because downstream demanded it, and to let techno-economic analysis and life-cycle assessment shape experiments from the beginning, not justify them at the end.

Volatile subsidies reward speed and certainty — the two things complex chemical systems almost never offer. Institutions like CABBI reward memory. Each iteration doesn’t reset. Each failure narrows the field. Each success arrives already synchronized with the rest of the system.

That institutional patience is why 3-HP finally moved.

Why the Round Matters

A round only works if every voice enters on time. No one rushes ahead. No one tries to win. Stability emerges from repetition and coordination.

That’s what we’re seeing now in 3-HP:

• Fermentation pH aligned with downstream processing
• Pathway choice aligned with oxygen demand and reactor physics
• Titers aligned with separation economics
• Process design aligned with real offtake requirements

Acrylic acid producers don’t want hero batches. They want continuous, spec-tight supply. Diaper makers don’t care how clever the pathway is — only that absorption works, every time. Persistence, it turns out, is the real end use.

3-HP didn’t fail because it couldn’t row. It failed because no one was rowing in time.

Gently, Downstream

Back at ISEE, the conversation wasn’t about a single molecule. It was about whether the bioeconomy could learn to synchronize feedstocks, machines, policy, water, and markets into something that actually moves.

3-HP is no longer a molecule of the future. It’s a molecule of the present — not because it finally learned to work harder, but because the system around it learned to move together.

The Department of Energy didn’t try to row the boat for renewable chemicals. It made sure the rowers had time to learn the song.

And once they did, the molecule stopped fighting the stream.

Row, row, row your boat — gently, downstream.