Picrophilus is an extremely acidophilic genus within Euryarchaeota. These microbes are the most acidophilic organisms currently known,[2] with the ability to grow at a pH of less than 0.5.[3] They were first isolated from samples taken from acidic hot springs and dry hot soil in Hokkaido (Japan). They are obligate acidophiles and are unable to maintain their membrane integrity at pH values above 4. While phylogenetically related to other organisms within Thermoplasmata, unlike Thermoplasma and Ferroplasma, Picrophilus contains an S-layer cell wall.
^C.Michael Hogan. 2010. Extremophile. eds. E.Monosson and C.Cleveland. Encyclopedia of Earth. National Council for Science and the Environment, Washington DC.
Thuermer, Andrea; Voigt, Birgit; Angelov, Angel; Albrecht, Dirk; et al. (December 2011). "Proteomic analysis of the extremely thermoacidophilic archaeon Picrophilus torridus at pH and temperature values close to its growth limit". Proteomics. 11 (23): 4559–4568. doi:10.1002/pmic.201000829. PMID22114103. S2CID25035919.
