Auribacterota

Auribacterota is a candidate bacterial phylum of uncultured anaerobes first found in gold mine fluids. The name comes from Latin aurum (gold). It is known only from metagenomes.^[1][2]

Auribacterota
Scientific classification
Kingdom:	Bacteria
Phylum:	Auribacterota Williams et al. 2022
Classes
"Candidatus Ancaeobacteria" Williams et al. 2022 "Candidatus Auribacteria" Williams et al. 2022 "Candidatus Erginobacteria" Williams et al. 2022 "Candidatus Tritonobacteria" Williams et al. 2022
Synonyms
Candidatus Aureabacteria Momper et al. 2017 emend. Williams et al. 2022 SURF-CP-2

These bacteria are strict fermenters. They eat sugars and amino acids, and make H₂ and H₂S. No oxygen is used. Some of these bacteria have gas vesicles or pili.^[2]

The bacteria live in anoxic water columns, sediments, and subsurface. They are common in Ace Lake, Antarctica (up to 4% of microbes).^[2] They help break down dead stuff and cycle sulfur.^[3]

There are four candidate classes. Type species: "Candidatus Auribacter fodinae".

Taxonomy

The phylum Auribacterota is not validly published and remains a candidate phylum. It was proposed by Williams et al. (2022) based on metagenome-assembled genomes (MAGs) from Ace Lake, a meromictic lake in Antarctica. The taxonomy includes four candidate classes, each containing novel genera and species identified from high-quality MAGs:

• Candidatus Ancaeobacteria: Includes "Candidatus Ancaeobacter aquaticus".^[4]
• Candidatus Auribacteria: Includes "Candidatus Auribacter fodinae" (type species, from subsurface fluids).^[4]
• Candidatus Erginobacteria: Includes "Candidatus Erginobacter occultus".^[4]
• Candidatus Tritonobacteria: Includes "Candidatus Tritonobacter lacicola".^[4]

Additional genera from Ace Lake include "Candidatus Euphemobacter frigidus" and "Candidatus Theseobacter exili". Phylogenetic analyses place Auribacterota among the "microbial dark matter" phyla, distinct from well-characterized bacterial lineages.