Pyrodictium is an interesting example of a prokaryote whose growth temperature optimum lies at or even above 100°C; the optimum being 105°C. Cells of
Pyrodictium are irregularly disc-shaped and grow in culture as a mycelium-like layer attached to crystals of elemental sulfur; the cell mass consists of a network of fibers to which individual cells are attached. The fibers are hollow and consist of protein arranged in a fashion similiar to that of bacterial flagella. The filaments do not function in motility but instead as organs of attachement, and the cell walls of
Pyrodictium are composed of glycoprotein. Physiologically,
Pyrodictium is a strict anaerobe that grows chemolithotrophically on H
2 with S
0 as electron acceptor or chemoorganotrophically on complex mixtures of organic compounds.
Taken from the text Brock Biology of Microorganisms (10th ed.). Madigan, M.T., Martinko, J.M., and Parker, J. 2003. Prentice Hall. 466p.