Is green jet fuel cooked in bioreactors in Texas?

Porto Alegre (Brazil)In a discreet laboratory complex in Houston, the company Cemvita is developing technologies to turn carbon dioxide and waste into valuable products. Its founder and scientific director, Tara Karimi, says the company’s mission is simple but radical: "To transform carbon dioxide and industrial waste into high-value products such as fuels, fertilizers, and cosmetics."

ARA spoke with Karimi in the Brazilian city of Porto Alegre, during the events of Caldeira Week, which the newspaper attended at the invitation of the Caldeira Institute, a technology hub in the capital of the state of Rio Grande do Sul that promotes innovation and sustainability projects, aiming to position itself as a global reference center for startups, new technologies, and solutions to the challenges posed by climate change.

Founded in 2017 by Karimi and her brother Moji, Cemvita has developed a biotechnology platform called FermWorks, designed to engineer microorganisms capable of converting CO₂ or organic waste into what they call FermOil — a base oil that can be refined into aviation fuel, detergents, or creams. "Our process involves zero deforestation and can yield a variety of products. The oil we produce can be used not only for fuel, but also for personal care and cleaning products", explains Karimi.

To date, their most ambitious project has been in the field of sustainable aviation fuels (SAF), an emerging market driven by pressure on the aviation industry to reduce emissions. In 2023, United Airlines signed a 20-year contract with Cemvita to supply 50 million gallons of alternative fuel annually. "Our product emits five times less carbon than the SAF currently on the market because we start the process with carbon dioxide. We turn the problem into a raw material", says Karimi, adding that the company is also in talks with European airlines to develop similar programs.

Cemvita’s scientific approach — based on synthetic biology to convert CO₂ into fuels and chemicals — is innovative but still highly experimental. Despite its potential to reduce emissions, its large-scale viability remains uncertain, given current energy and economic costs. Furthermore, the genetic manipulation of microorganisms raises questions about safety and environmental control. In any case, Cemvita offers a disruptive vision, though it still needs independent validation and transparency of results to establish itself as a real alternative to petroleum.

Economic viability?

The business model depends not only on technology but also — crucially — on economic viability, especially at a time when the U.S. president, Donald Trump, repeats the slogan "Drill, baby, drill!" as if climate change were not an issue. "From the beginning, we wanted to build a self-sustaining business, without relying on public funds or additional loans. That’s why we decided to start with waste. If you use a waste stream, you drastically reduce production costs", explains the co-founder. The result, she says, is a product already cheaper than conventional SAF, because it doesn’t depend on expensive raw materials like soybean oil or sugarcane.

Cemvita’s distinctive advantage also lies in its ability to generate multiple revenue streams from the same process. About 30% of the initial waste is converted into oil; the rest is used to produce biofertilizers and biostimulants for reforestation or regenerative agriculture. "Our process yields two products and generates virtually no waste. What’s left helps improve soils and restore biodiversity", says Karimi.

This "nature-positive" approach is central to Cemvita’s business philosophy. "We don’t just want to reduce emissions; we want to have a positive impact on biodiversity and the environment", she emphasizes. This vision has also shaped the company’s international expansion strategy: Brazil has been one of the first countries chosen for production outside the United States.

"In our plan, all core values are based on sustainability. And we see that these values are deeply rooted in Brazil. The country already has a consolidated infrastructure in biomanufacturing and the circular economy, with success stories in biofuels such as bioethanol and biodiesel", she says.

For Karimi, the key is to build on what already works. "Let’s start in a country with a track record of success and an existing infrastructure. We add value: we’re not here to replace anything, but to complement and improve what already exists." The company is also committed to collaborating with local suppliers to reduce import dependence and strengthen local scientific talent. "We want to work with local suppliers and tap into existing talent. All we need is additional training to adapt it to our technology," she adds.

Cemvita’s future now depends on scaling up to industrial production. The company plans to produce up to 500 barrels of sustainable oil per day in its first commercial plant, while maintaining minimal environmental impact — using 99% less land and water compared to traditional production. This industrial capacity could turn a laboratory innovation into a real alternative in the global energy market.

All of these positions Cemvita as one of the most promising biotechnology firms in the climate sector. In 2025, the company was recognized by the Greentown Labs consortium as Climate Impact Startup of the Year. It’s no small achievement: the industry already sees Cemvita’s model as one of the most promising paths to decarbonize hard-to-abate sectors such as aviation and petrochemicals. Tara Karimi sums up her philosophy in a single sentence that captures the revolution she hopes to spark from Houston: "Sustainability isn’t a luxury or a cost. It’s a business."