CO-converting enzymes for sustainable biotechnology: from mechanisms to application.

To realize a circular, carbon-neutral economy, it will become important to utilize the greenhouse gas CO as a sustainable carbon source. Carboxylases, the enzymes that capture and convert gaseous CO are the prime candidates to pave the way towards realizing this vision of a CO-based bio-economy. In the last couple of years, the interest in using and engineering carboxylases has been steadily growing. Here, we discuss how basic research on the mechanism of CO binding and activation by carboxylases opened the way to develop new-to-nature CO-fixing enzymes that found application in the development of synthetic CO-fixation pathways and their further realization in vitro and in vivo. These pioneering efforts in the field pave the way to realize a diverse CO-fixation biochemistry that can find application in biocatalysis, biotechnology, and artificial photosynthesis.