High-pressure fermentation for optimizing CO2 utilization

Biological processes can be used for the conversion of greenhouse gases into added-value chemicals. With a new, unique high-pressure (up to 10 bars) fermenter, the Flemish Institute for Technology Research (VITO; Mol, Belgium; www.vito.be) is researching how these processes can be optimized.

The custom-made bioreactor, which was installed a year ago as part of the BioRECO2VER project (www.bioreco2ver.eu), is equipped with all relevant peripheral equipment to be able to measure and control the fermentation of CO₂ and hydrogen, or oxygen, methane or synthesis gas (syngas; hydrogen and carbon monoxide), which are metabolized by specialized bacteria into useful chemicals. The microbiological conversion takes place in the liquid phase, while the reagents are injected in a gaseous state. Operating at higher pressure increases the solubility of the gases, thereby increasing the rate of fermentation.

To overcome several of the existing technical and economic barriers for CO₂ conversion by industrial biotechnology, VITO focuses, with the new installation, on maximizing gas transfer in bioreactors and improving scalability, as well as studying the influence of various parameters, such as pressure, temperature and composition and dosage of the gas phase on fermentation. The high-pressure fermenter also has a membrane-filtration unit to retain the micro-organisms in the reactor.

BioRECO2VER is a consortium of twelve companies, research institutions and universities investigating the technical feasibility of energy-efficient and sustainable biochemical conversion of CO₂ — from industrial point sources like refineries and cement production plants — into chemical building blocks, such as isobutene and lactate. The project is funded under the European Union’s Horizon 2020 research and innovation program.