Prehistoric Microbes Valorize Carbon Dioxide under High Pressure to 'Green Gas'

(Krajete GmbH/TechXplore) A completely new kind of bioreactor for the biological production of methane has enabled the use of extremely high pressure levels for the first time—and set new efficiency standards for the conversion of CO₂ and H₂ into methane. This significant improvement compared with conventional bioreactors is down to billions of microorganisms that only truly come to life under extreme pressure, as well as Austrian company Krajete GmbH, which designed the bioreactor and has now built the first pilot plant for testing the technology. Successful installation required a combination of experience of implementing chemical facilities and biological expertise.

One such idea, the brainchild of Austrian company Krajete GmbH, focuses on production of ecofriendly gas—using gas fermentation to produce methane from CO2. The company has developed a bioreactor that delivers enormous gains in the conversion rate by using extremely high pressure. The key to this success is what are called archaea—microorganisms that lived in prehistoric times and are used to extreme pressure conditions. And helpfully they can also transform CO2 into "green" natural gas.

"Our plant has achieved previously unattainable conversion rates, because higher pressure speeds up chemical transformation processes," explained Alexander Krajete, CEO of Krajete GmbH. "In addition,the archaea fermentation process uses hydrogen. This means that CO₂ normally produced during biological fermentation is also converted into methane, and does not represent a contaminant anymore as with biomass fermentation. So with this higher yield the plant produces virtually pure methane instead of impure biogas. Based on this principle, almost all CO₂ containing emission gases can be directly upgraded."

The company had already managed to "tame" archaea for natural gas production in 2013. Five patents were registered to safeguard this success. Development of the high-performance bioreactor will allow the company to capitalize fully on the potential of this approach. "Our pilot facility has shown that we can obtain 500 liters of methane per hour from only ten liters of liquid at a pressure of 15 bar. Those figures for biosynthetic natural gas production are unrivaled anywhere in the world." READ MORE