Startup with CU roots channeling microorganisms to make “green” cement


A Colorado company is channeling the industriousness of microorganisms to grow carbon-free cement in a process similar to how corals build reefs or oysters produce shells.

Startup Prometheus Materials recently closed an $8 million Series A funding round that included participation from the Microsoft Climate Innovation Fund and Sofinnova Partners, a European venture capital firm.

The technology is revolutionary, but its basis has been around for billions of years, according to Loren Burnett, co-founder and CEO of the company.

The production of what will ultimately be building materials begins with microalgae and provides them with what they need to do what they do naturally: biomineralization. It is the process by which living organisms produce minerals that form structures such as shells and reefs.

What started as research by four professors from the University of Colorado at Boulder has moved to a production site in Longmont. There, the company will manufacture biocement, a carbon-free alternative to so-called portland cement, the most common type of cement and a basic ingredient in concrete.

Concrete is one of the most widely used materials in the world, Burnett said. “And cement, which is the key component of concrete, is responsible for 7-8% of Earth’s carbon dioxide emissions on an annual basis.”

The global building stock is expected to double by 2060 even as the need to reduce greenhouse gas emissions increases, he added. Burnett, a self-proclaimed serial entrepreneur, met the professors at UC, decided to license the technology, and together with the professors formed Prometheus Materials, the sixth company he started.

“I realized very quickly that what they were working with had enormous potential to have a significant impact on the Earth by decarbonizing concrete,” Burnett said.

Wil Srubar III was the principal investigator for UC scientists and engineers working under a Department of Defense grant. Faculty areas of expertise include microbiology, biochemistry, materials science, and structural engineering.

Srubar is co-founder and chief technology advisor for Prometheus Materials. Professors Jeff Cameron, Sherri Cook and Mija Hubler are also co-founders.

As for how the team settled on the microalgae, Srubar said he thinks nature has figured out a lot. “We just have to be more careful.”

Scientists looked at a variety of microorganisms that create calcium carbonate, a main component of limestone, through their own metabolic activity.

Limestone, formed from the skeletal fragments of marine organisms, is mined, ground, and heated to around 2,600 degrees Fahrenheit to make cement. The process releases carbon dioxide, the main heat-trapping gas that causes climate change.

The researchers explored whether there was “a more efficient and harmonious way” to produce the material, Srubar said. “We were very inspired by natural processes and the innate ability of microorganisms to do this.”

The microalgae produce the minerals using photosynthesis, Srubar said. “We don’t even have to give them anything. They are powered by the sun, carbon dioxide.

The company uses seawater to grow a culture of microalgae, which create the mineral. When the water is removed, what remains is called biocement. It is combined with rocks and sand to form concrete.

The materials needed to produce the bio-based cement are readily available around the world, Srubar said. Carbon dioxide can simply be carried from the atmosphere.

Burnett said the goal is to license the patent-pending technology to large companies capable of producing and distributing the biocement at scale. The cement will be marketed to architects, engineers, property developers and others in the construction industry.

Prometheus recently completed a pilot project with its product with a major company that Burnett declined to disclose. Bio-Cement has been tested at CU and will go through a formal certification process with the American Society for Testing and Materials.

“I’ve never been at a company where I felt like we had a clear path to being able to have a meaningful global impact and we do,” Burnett said.


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