Hypertermofilit

Hypertermofilit are microorganisms that grow optimally at very high temperatures, typically above 80°C, with some thriving near or beyond 100°C. The group is largely composed of archaea, though a minority of bacteria also include hypertermofilit. They inhabit geothermally heated environments such as deep-sea hydrothermal vents, hot springs, and volcanic regions where external temperatures limit the growth of most life.

Adaptations and biology

Hypertermofilit possess cellular and molecular features that confer stability at extreme heat. Their membranes often consist of ether-linked lipids, including tetraether lipids, which provide rigidity and protection at high temperatures. They rely on thermally stable proteins and enzymes, supported by chaperone systems and heat-stable structural components. DNA stabilization is aided by specialized enzymes such as reverse gyrase, and by abundant histone-like proteins that help protect genetic material. Many hypertermofilit maintain high intracellular concentrations of compatible solutes to stabilize macromolecules.

Metabolism and ecology

Most hypertermofilit are chemolithoautotrophs or chemoorganoautotrophs, extracting energy from inorganic compounds such as molecular hydrogen, hydrogen sulfide, or elemental sulfur. Carbon is fixed using diverse metabolic pathways, and respiration can be aerobic or anaerobic, depending on the organism and environment. They occupy ecological niches in extreme habitats, contributing to primary production and participating in elemental cycling within hydrothermal ecosystems.

Importance and applications

Hypertermofilit are central to studies of life's limits and early evolution, given their ability to thrive at temperatures resembling ancient Earth conditions. Their thermostable enzymes, including DNA polymerases and other biocatalysts, have broad industrial and research applications, notably in high-temperature processes and molecular biology techniques.