Carbon dioxide (CO2) is the main nutrient needed by microalgae to grow into a protein-rich biomass. CO2 be obtained from the air around us, but only at very low concentrations (0.04%). This poses an obstacle to recycle atmospheric CO2 in large scale production of microalgae, since microalgae require large amounts of highly concentrated carbon dioxide to grow fast.

To face this challenge, ProFuture’s researchers at the University of Twente, in the Netherlands, are now developing a unique process to concentrate CO2 from ambient air in an efficient and sustainable way.

In this process, a large amount of air is blown through a system containing particles – also known as sorbent particles - that are able to “trap” the CO2 temporarily. After the CO2 capture, the system is heated at low pressure, causing the CO2 to be released again from the particles. As a result, the system vents out highly concentrated CO2, which can be directly given to the algae.

The ProFuture Direct Air Capture facility uses an efficient low pressure drop concept, meaning it consumes less energy than other similar technologies. The process also recycles the sorbent particles to maximize efficiency.

To make this process CO2 net negative – meaning that the process removes as much carbon as it emits - the energy consumption and the CO2 footprint (CO2 emission) must also be considered. ProFuture’s calculations showed that when ProFuture’s

Direct Air Capture Facility uses renewable energy from the sun or wind, the CO2 emission is 0.1 kg CO2 per kg of CO2 captured from the air, thus resulting in a net removal of 0.9 kg CO2 per kg of CO2 captured.

ProFuture will now test the cultivation of microalgae using CO2 from Direct Air Capture under the real-life conditions of the microalgae production facility Allmicroalgae, in Portugal.

This system aims to be operational in the course of 2021. Building this facility comes as a challenging milestone, but an important one to further develop and apply this innovative technology.