Thermofiilisten

Thermofiilisten is a term used in microbiology to describe organisms that grow optimally at high temperatures. The name derives from Greek thermo- meaning heat and philos meaning loving. In practice, thermofiilisten include both bacteria and archaea that tolerate or require hot environments.

These organisms inhabit natural hot environments such as geothermal springs, deep-sea hydrothermal vents, and volcanic soils, and they are also found in man-made settings that reach elevated temperatures, including compost piles and certain industrial processes. Temperature optima vary by group; many thrive around 45–80°C, while hyperthermophiles surpass 80°C and some can withstand brief exposure to even higher temperatures.

Physiological adaptations include heat-stable enzymes, membranes enriched in saturated and branched lipids (archaeal membranes often contain ether-linked lipids), and protective molecular chaperones. Some thermofiilisten possess reverse gyrase to help stabilize DNA at high temperature, contributing to genome integrity under heat stress.

Metabolism among thermofiilisten ranges from chemolithoautotrophy, using inorganic energy sources such as sulfur or hydrogen to fix carbon dioxide, to chemoorganoheterotrophy, utilizing organic compounds. They can be aerobic, anaerobic, or microaerophilic depending on the species. In ecosystems, they play roles in inorganic element cycling and organic matter turnover in extreme environments.

Industrial and scientific relevance is notable: thermophiles contribute to nutrient cycling in hot habitats and provide thermostable enzymes used in biotechnology. Notable examples include Thermus aquaticus, Thermus thermophilus, Thermotoga maritima, Pyrococcus furiosus, and Sulfolobus solfataricus. Their enzymes withstand high temperatures, enabling processes such as polymerase chain reaction and high-temperature biocatalysis.