Tags: Archaea.
In taxonomy the Thermoplasmatales are an order of the Thermoplasmata. All are acidophiles growing optimally at pH below 2. Picrophilus is currently the most acidophilic of all known organisms growing at a minimum pH of 0.06. Many of these organisms do not contain a cell wall although this is not true in the case of Picrophilus. Most of members of the Thermotoplasmata are thermophilic.