Thermoplasma acidophilum

Thermoplasma acidophilum is an archaeon, the type species of its genus. T. acidophilum was originally isolated from a self-heating coal refuse pile, at pH 2 and 59 °C. Its genome has been sequenced.

It is highly flagellated and grows optimally at 56 °C (133 °F) and pH 1.8. The size of a cell is about 1 μm. T. acidophilum lacks a cell wall and the cell membrane is exposed directly outside. T. acidophilum shows various cell shapes depending upon growth conditions and stages.