Details for Pyrolobus

Participants Studying this Organism
Thermal Features for this Organism


NCBI Taxonomy ID: 54251
NCBI Taxonomy Rank: Genus
Pyrolobus is an interesting example of a prokaryote whose growth temperature optimum lies at or even above 100°C; the optimum being 106°C. Pyrolobus fumarrii currently holds the record for the most thermophilic of all known organisms - its growth temperature maximum is 113°C (notably, P. fumarrii is unable to grow below 90°C because it is too cold!). Pyrolobus lives in the wall s of "black smoker" hydrothermal vent chimneys where, because of its autotrophic abilities, it is possibly a major source of primary productivity in this otherwise inorganic environment. Pyrolobus cells are coccoid-shaped and the cell wall is composed of protein. The organism is an obligate H2 chemolithotroph, growing at the expense of H2 oxidation coupled to the reduction of NO3- (to NH4+), S2O32- (to H2S), or very low concentrations of O2 (to H2O). Besides its extremely thermophilic nature, Pyrolobus is also resistant to termperatures substantially above its growth temperature maximum. For example, cultures of P. fumarrii survive autoclaving (121°C) for 1 h, a condition that even bacterial endospores cannot withstand. Considering the hydrothermal vent habitat of this organism, where periodic shifts in the temperature may be a regular occurrence, high heat resistance would be of great survival value.
Taken from the text Brock Biology of Microorganisms (10th ed.). Madigan, M.T., Martinko, J.M., and Parker, J. 2003. Prentice Hall. 466-467p.