Valuable Waste: Synata Bio’s Microbes Convert Waste CO2 Into Ethanol

Synata Bio’s microbes love to eat CO₂. In a gas stream, give them hydrogen and they eat even more CO₂.

The CO₂-eating microorganisms release ethanol via gas fermentation, cracking open a potential revenue stream for companies looking to transform carbon emissions into sustainable products.

“What I like about our biocatalyst is the fact that it not only enables the CO₂ from a utilization perspective, but it also enables the hydrogen economy,” Synata Bio CEO Tim Cesarek told Hart Energy. “It needs both. … They live a long time. …They’re very robust in terms of not only their ability to convert gases at a very high rate to ethanol, i.e. selectivity, but they have a capacity to last over hours. Let’s just say thousands of hours.”

Turning waste gas into ethanol and other potential carbon-neutral products is considered an encouraging way to mitigate climate change. Biotech companies are using catalysts to create renewable fuel sources like ethanol, which can be blended with gasoline or used as a standalone fuel such as sustainable aviation fuel (SAF) to produce fewer greenhouse-gas emissions than petroleum-based fuels.

The process is one of the ways some companies are taking steps to turn carbon emissions into products. Others include LanzaTech, which utilizes an engineered bacterium called Clostridium autoethanogenum to convert waste carbon selectively into ethanol, acetone or isopropanol.

Synata Bio’s process uses a fermentation process to convert synthesis gas and waste gas from feedstocks into ethanol.

“One unique thing about our microorganism is it has been made through evolutionary biology and not genetically modified,” Cesarek said. “If you think about it, it’s been survival of the fittest.”

The journey

It took the Illinois-based company, which originally started as Coskata in 2005, about 15 years to identify the right catalyst for the job. The journey included finding “those little buggers that like to live longer and produce more ethanol,” identifying species that can withstand various contaminants and singling out overachievers. “We isolate those microorganisms and we make more of those. So, it’s taken time to do that. … But the technology, I believe, now is ready for prime time.”

The technology, which has already been tested at pilot and demonstration-scale levels, is scaling up further. Synata Bio partnered with Henan Energy Group to deploy the technology at commercial scale at a waste carbon-to-ethanol facility being built in China as part of the Sylonto joint venture project launched in 2023.

“That plant will roughly take in 75 kilotons of waste gas made up of CO₂, carbon monoxide (CO), hydrogen that is coming from a coal-to-methanol facility… [for conversion] into ethanol and then further convert it into ethyl acetate,” Cesarek said during a Houston CCUS conference. “We’ll be producing roughly 50 kilotons of ethanol through that process.”

The company will also make, as part of the process, about 2,500 tons to 3,000 tons of single cell proteins. These dead cells are actually high-value proteins rich in amino acids and can be sold as fish food, he said.

A $4.5 million boost

Synata Bio’s efforts recently got a multi-million dollar boost. China’s National Development and Reform Commission awarded the company a $4.5 million grant for the Sylonto project, the company said Nov. 19. The commercial waste carbon-to-ethanol facility is being integrated into the Henan Energy Group’s chemicals production site Henan Longyu.

Other partners in the project include financing partner Zhicheng and HOTO Engineering, the project’s engineering partner and site contractor.

“When completed, Sylonto will transform on-site waste gases into 50,000 tons of chemical-grade ethanol per year, with plans to expand that to 500,000 tons annually by 2028,” according to the release.

Cesarek said Synata Bio’s process is less expensive than using the Fischer-Tropsch (FT) chemical process to produce ethanol. The FT process converts a mix of hydrogen and CO into what he called a “broth of fuels” that need to be further processed to make products.

“The valorization of this waste gas to make an ethanol product that can compete with the fossil alternative—being in this case a synthetic ethanol—would be the next best alternative,” Cesarek said during the conference session. “So, there are certain markets where that’s the case. However, we have a philosophy in this business we’re building that we have to make money on an economic profit basis first. And to the extent that there’s carbon value to be had, that’s just icing on the cake.”

Synata Bio seeks markets with ethanol needs where it can be a point source for waste gases and leverage existing infrastructure, he said. These include markets that use ethanol as a feedstock for SAF.

The ethanol produced also enables the production of ethylene, a building block for many olefins, he added.

Looking ahead

Synata Bio licenses its technology, but Cesarek sees opportunities for a tolling model in the future. “Gas comes in over the fence. For a fixed fee, we toll that gas into ethanol, ethylene or some other olefin that that petrochemical facility would utilize,” he said.

However, there are capital constraints for an early-stage company like Synata Bio, Cesarek later told Hart.

“If capital weren’t a constraint, our offering would simply be a tolling model. With capital being a constraint, you’ve got to start somewhere and you’ve got to make money somewhere,” he said.

Infrastructure is necessary, but there are risks.

“My hope is that we find private equity, we find private equity in the form of infrastructure that is willing to take on a little more risk where they recognize that an 8% return is probably not going to compensate them enough for the risks they’re taking,” he said. “But they’ll take on a little commodity risk. They’ll take on a little completion risk. They’ll take on a little budgetary risk. But those are hard to find because, again, it’s a transition.

“And I will tell you, this transition is not linear. It’s not. There will be fits and starts along the way.”