Nitrogenase is one of the few biological systems known to break the strong triple nitrogen-nitrogen bond, thereby allowing fixed nitrogen to enter the biosphere. In biological nitrogen fixation, nitrogenase reduces dinitrogen to ammonia, along with the evolution of hydrogen. While the biochemistry of this process has been studied for decades, the discovery of hydrocarbon production by nitrogenase has only been reported recently.

Here, the authors elucidate the details of the enzymatic reactions that underlie the production of hydrocarbons by nitrogenase. The team demonstrates that, in addition to nitrogenase’s previously characterized role in converting nitrogen to ammonia, the enzyme can also generate short-chained hydrocarbons and hydrogen through the reduction of water and protons. Mechanistic experiments revealed that the same FeMoco active site that catalyzes N2 reduction also mediates hydrocarbon formation, suggesting that these two processes are intricately linked.

This work highlights the versatility of nitrogenase and provides insights into the fundamental chemistry underlying the enzyme’s substrate promiscuity. The findings expand our understanding of nitrogenase's capabilities and contribute to the development of novel strategies for hydrocarbon production and nitrogen fixation in industrial and agricultural settings.