Thermophile

Thermophilicity ( from Ancient Greek θερμός thermos " hot " and φίλος philos " loving" ) is the property of living beings to prefer high temperatures ( 45-80 ° C). Living things with this property are called thermophilic. If the preferred temperature range above 80 ° C, one speaks of hyperthermophilic organisms.

Thermophilic organisms are found especially among the archaea and ( rarely) in the bacteria. For some archaea the optimal living conditions are only at well over 70 ° C; they mainly live in hot springs and geysers. Some thermophilic bacteria and fungi (eg Chaetomium thermophilum ) preferably colonize compost heap, inside which by rotting the temperature rose to about 45 ° C.

In the deep sea there are in areas with volcanic activity - especially at mid-ocean ridges - ecosystems, where water temperatures due to heating by rising magma and the high hydrostatic pressure even exceed 100 ° C, but which nevertheless contain a rich biological community. As the current leader among the hyperthermophilic microorganisms Archaee Strain 121 nor its population doubled at 121 ° C every 24 hours apply ( discovered in 2003 in a black smokers in the Juan de Fuca Ridge ), and the Archaee Methanopyrus kandleri, which also can grow at 122 ° C (1991 discovered on a black smokers in the Gulf of California). In order to solve these from the former record holder Pyrolobus fumarii, which is to grow up to 113 ° C in the situation. At the chimneys black smoke lives and the worm Alvinella pompe jana, temperatures up to 80 ° C tolerated in its habitat, and thus holds the record among the thermophilic eukaryotes.

It is believed that the absolute upper limit for life of any kind to about 150 ° C, since at higher temperatures the DNA ( the carrier of genetic information ) with such a high speed degrades by hydrolysis that every currently known DNA repair system would be overtaxed. Water bears are able to survive under certain conditions and with a certain probability, temperatures up to 151 ° C, confirming provisionally this border. Nevertheless, no one can exclude with certainty the existence of so-called ultra- thermophilic organisms. These are still hypothetical creatures could have evolved mechanisms by which they survive at even higher temperatures, as can be found eg in some hot springs, near which colonies of Pyrolobus fumarii exist; where temperatures of up to 350 ° C were measured.

Also land animals can be thermophilic. This is particularly true for many animals in the desert.

In the technical Microbiology (Biotechnology) bacterial processes then run at thermophilic conditions, if they occur at about 50 ° C. If the temperatures are lower, one speaks of mesophilic conditions (30-40 ° C) and psychrophilic conditions (below 20 ° C). Both the fermentation and composting can be operated at thermophilic conditions.