Summary
Candidatus
Dormibacterota is an uncultured bacterial phylum found predominantly in soil that is present in high abundances within cold desert soils. Here, we interrogate nine metagenome‐assembled genomes (
MAGs
), including six new
MAGs
derived from soil metagenomes obtained from two eastern Antarctic sites. Phylogenomic and taxonomic analyses revealed these
MAGs
represent four genera and five species, representing two order‐level clades within
Ca
. Dormibacterota. Metabolic reconstructions of these
MAGs
revealed the potential for aerobic metabolism, and versatile adaptations enabling persistence in the ‘extreme’ Antarctic environment. Primary amongst these adaptations were abilities to scavenge atmospheric
H
2
and
CO
as energy sources, as well as using the energy derived from
H
2
oxidation to fix atmospheric
CO
2
via the
Calvin–Bassham–Benson
cycle, using a
RuBisCO
type
IE
. We propose that these allow
Ca
. Dormibacterota to persist using
H
2
oxidation and grow using atmospheric chemosynthesis in terrestrial Antarctica. Fluorescence
in situ
hybridization revealed
Ca
. Dormibacterota to be coccoid cells, 0.3–1.4 μm in diameter, with some cells exhibiting the potential for a symbiotic or syntrophic lifestyle.