Hyperthermophiles are microorganisms that love to grow optimally in
extremely hot environments, with optimum temperatures for growth of 80 °C and
above. Most of the hyperthermophiles are represented by archaea; and only a few
bacteria, such as Geothermobacterium ferrireducens, and members of the genera
Aquifex and Thermotoga have been reported to grow at temperatures closer to 100 °C.
Several archaea, on the other hand, such as Methanopyrus kandleri, Geogemma
barossii, Pyrolobus fumarii, Pyrococcus kukulkanii, Pyrodictium occultum, etc.
isolated from terrestrial hot springs, marine hydrothermal vents, or other hyperthermal
environments have been reported to grow optimally even above the boiling point of
water. The discovery of this astonishing group of microorganisms has not only
provided us with the model systems to study the structural and functional dynamics of
the biomolecules, and to understand the molecular mechanisms of their adaptation to
such high temperature, not even closer to what can be endured by other life forms, but
also have boosted the biotechnological industry to search for new products, particularly
enzymes with unique characteristics, from them. This chapter has exhaustively
reviewed the different hyperthermal environments on Earth’s surface and the
hyperthermophilic microbial diversity in such environments; mechanisms of adaptation
of the hyperthermophiles, especially with regard to the adaptations of the membrane
structures, maintenance of the structures of the nucleic acids and proteins; and their
diverse applications in human welfare.
Keywords: Adaptation of the membrane structures, Amylases, Cellulases, Extremophiles, Hot springs, Hydrothermal vents, Hyperthermophiles, Lipases, Maintenance of nucleic acid structures, Maintenance of protein structures, Proteases, Polyextremophiles, Pullulanases, Thermophiles, Thermoprotection, Thermostable enzymes.