Scientists have discovered a new enzyme that can absorb CO2 more efficiently. Researchers think its ability to speed up CO2 absorption while withstanding harsh environments could make it a groundbreaking new method for reducing carbon emissions in industrial applications.
The super-enzyme called CA-KR1 was discovered by a team of Greek researchers led by Dr. Georgios Skretas at BSRC Fleming. The scientists developed a metagenomic tool to analyze genomes contained in an environmental sample. They aimed to identify a super heat-resistant biotechnological enzyme. After scanning millions of genes from open-access metagenomic databases, they stumbled across a promising biocatalyst– a natural substance that improves the rate of chemical reactions. The sample originated from the Kirishima region in Japan. Through this process, the scientists discovered CA-KR1, a highly stable carbonic enzyme that catalyzes the removal of water molecules from compounds.
CA-KR1 is highly adaptable to high temperatures and alkaline (basic) environments, functioning well above 80°C and pH above 11. PhD candidate Konstantinos Rigkos who was among the scientists playing a major role in the discovery explains that the enzyme not only enhances CO2 capture productivity by 90% at 90°C but also surpasses the standard biocatalyst’s performance in hot potassium carbonate (HPC) processes by allowing 90% CO2 removal at 80°C. Dr. Zarafeta, another leading researcher in the discovery, stated, “The CA-KR1 enzyme is perhaps the most robust biocatalyst (carbonic anhydrase) for efficient CO2 capture in HPC conditions reported to date.”
The efficiency of this enzyme makes it a promising solution for alternative ways to reduce industrial CO2 emissions. The researchers are confident it could greatly advance sustainable technology like industrial biomimetic CO2 capture instruments.
Reducing industrial carbon emissions is a huge step towards a sustainable future and circular economy. The discovery is one of the numerous different ways chemical and biological technologies serve this purpose. The umbrella term for processes that aim to absorb CO2 is carbon capture, utilization, and storage (CCUS), while the specific technologies that reduce carbon dioxide are called carbon capture and storage technologies (CCS). Their purpose is to capture CO2 generated by fossil fuels before it mixes into the atmosphere, and transport and store it underground in geological formations. Currently, CCS projects store almost 45 million tons of CO2 annually, and they do so through various processes.
The current most widely used chemical CCS project is using point-sourced carbon capture in power plants. The process separates CO2 emissions from a power plant’s gas stream. Then the CO2 is compressed and transported for storage or enhanced oil recovery. Other methods include direct air capturing which uses air filters to catch CO2 directly from the atmosphere, using amines to isolate CO2 from other gasses, and using nano-materials to separate and store CO2 at a lower pressure compared to other technologies. However, although these processes have their advantages, they pose several limitations like high energy consumption, cost, and possessing technology that is limited and/or at its early stages.
Another key method used in CO2 removal processes is hot potassium carbonate (HPC). Like amines, HPC is a chemical technique used in carbon dioxide absorption, and it accomplishes CCUS aims by taking in compressed flue gas and returning two gas-phase products: low-CO2 flue gas which gets directly discharged into the atmosphere, and high-purity CO2. In contrast to amine absorption technologies, HPC is completely resistant to oxidative and thermal degradation, more cost-effective, and uses potassium carbonate which is a non-toxic and non-volatile compound that is environmentally friendly. However, this does not make HPC perfect, and there are ongoing developments to improve the process, namely making it even more energy efficient. This is where the CA-KR1 enzyme comes in; thanks to its adaptability to extreme environments, the enzyme carries proteins that significantly accelerate the dissolution of CO2 in water. This helps carbon dioxide be captured from industrial exhaust streams.
Although this technology is promising, it is important to be prudent. At its current state, carbon capture technology only addresses industrial emissions and fails to capture gasses emitted from cars and other domestic sources. Furthermore, installing facilities and building infrastructure is an expensive process. The progression of chemical discoveries of mechanisms like CA-KR1 could pave the way for more efficient uses of CCS methods. The continued advancement of such processes is crucial for moving towards a greener future and reaching the global aim of net zero emissions by 2050.
Edited by: Yağmur Ece Nisanoğlu