The order Thermoproteales contains some 5 genera which grow in temperatures of 60 to 102°C and with an optimum pH of 4-6. All cells in Thermoproteales are rods and are either strict anaerobes or faculatative aerobes.
Taken from the text Brock Biology of Microorganisms (10th ed.). Madigan, M.T., Martinko, J.M., and Parker, J. 2003. Prentice Hall. 464p.