Features and Applications of Halophilic Archaea

ABREVAYA, X. C.

Extremophiles: Sustainable resources and Biotechnological Implications

Wiley-Blackwell

Año: 2012;

The halophilic organisms are those able to live in saline environments, being the presence of salt (generally NaCl), a specific requisite for its growth. It is possible to find these kind of organisms in the three domains of life: Bacteria, Eukarya and Archaea (Litchfield, 1998). In particular, inside the Archaea domain have been found some of the most extreme halophilic microorganisms to date, requiring concentrations of NaCl next to saturation (between 3 y 5 M NaCl) for an optimal growth.   These haloarchaea lives in hypersaline environments in which the concentration of salts exceeds that of the seawater. Examples of these hypersaline ecosystems are salterns, hypersaline lakes and evaporitic water bodies as the crystallizer ponds of solar salterns (Oren, 2002; Oren, 1999a). These microorganisms have also being found in evaporitic deposits of millions of years (Fendrihan et al., 2006). The particular features of halophilic archaea and the environment in which inhabit makes these organisms interesting in areas of research as astrobiology and exobiology. This is because haloarchaea in particular are able to tolerate many types of environmental stresses, not only high salt concentrations, but also in high doses of UV or ionizing radiations, low levels of oxygen and extremes of temperature and pH. These particular characteristics leads to propose these organisms as models for study in these areas or “exophiles” because of its ability to survive extreme physicochemical conditions (DasSarma and DasSarma 2005; DasSarma, 2006).