Aerobic hydrocarbon oxidation in a novel archaeal lineage

Over the last decade, there has been significant advances in our understanding of anaerobic hydrocarbon oxidation in Archaea. While Bacteria are known to oxidise hydrocarbons aerobically, no aerobic hydrocarbon oxidation pathway has been found in Archaea. Here, we report the first aerobic hydrocarbon oxidizing archaeon in a novel order of the Syntropharchaeia. This order is represented by six metagenome-assembled genomes (MAGs) spanning three genera that are found in terrestrial and marine ecosystems. Our analysis revealed that MAGs belonging to one newly defined genus, Candidatus ‘Aerovita’, encode a bacterial copper monooxygenase complex with homology to bacterial hydrocarbon monooxygenases. The presence of other oxygen-dependent enzymes, such as haem-copper oxygen reductase, and the absence of the Wood-Ljungdahl pathway, indicate an aerobic lifestyle for the Ca . ‘Aerovita’ lineage. These findings support horizontal gene transfer between archaeal and bacterial domains facilitating the evolution of aerobic hydrocarbon-oxidizing archaea.