The upper temperature of life--where do we draw the line?

A new archaeal isolate has been reported that is capable of growing at up to 121 degrees C. The hyperthermophile, dubbed strain 121, grows chemoautotrophically using formate as an electron donor and FeIII as an electron acceptor and is closely related to members of the archaeal genera Pyrodictium and Pyrobaculum. Although the reported maximum growth temperature of strain 121 is 8 degrees C higher than the previous record holder (Pyrolobus fumarii; Tmax = 113 degrees C), the two organisms have virtually the same optimal growth temperatures.