Extremophiles can be divided into two categories
Here we are going to study some Types of Extremophiles…
1. Extremophilic organisms that require one or more extreme conditions to survive.
2. Extremotolerant organisms that can tolerate extreme conditions of one or more physical parameters even though they grow optimally at neutral conditions. Extremophiles include members of all three domains of life; bacteria, archaea, and eukarya.
These are classified according to the conditions in which they grow –
Thermophiles – Organisms growing at high temperature.
Hyperthermophiles – Organisms growing at very high temperature.
Psychrophiles – Organisms that grow at low temperature.
Acidophiles – Organisms thriving in habitats with acidic PH.
Alkaliphiles – Organisms thriving in habitats with basic PH.
Halophiles – Organisms that grow well in an environment with NaCl.
Radoduric – Organisms that grow well in the presence of high radiation.
Barophiles – Organisms that grow best under pressure.
Types of Extremophiles
1) Psychrophiles, literally meaning cold-loving.
2) They are organisms adapted to growth at low temperatures.
3) Having an optimum growth temperature of greater than 15°C and a maximum growth temperature of greater than 20°C and minimum of 0°C.
1) Thermophiles (literally heat lovers) are organisms that grow at temperatures above those (25-40°C) that sustain most life forms.
2) Typically, a thermophile shows maximum growth rates at temperatures above 45°C.
1) Hyperthermophiles are organisms that can survive and grow at extremely high temperatures (above 80°C).
2) Hypothermophiles are a type of thermophiles that can endure even higher temperatures than other thermophiles.
The optimum temperature of growth for hyperthermophiles is 80°C, but they can survive at temperatures higher than 100°C.
1) Acidophiles are organisms that can survive and thrive at highly acidic conditions (usually at pH 2.0).
2) Acidophilic microorganisms thrive in extremely low pH natural and man-made environments such as acidic lakes, some hydrothermal systems, acid sulfate soils, sulfidic regoliths, and ores, as well as metal and coal mine impacted environments.
2) Alkaliphiles are of two types; obligate alkaliphiles growing only in environments with pH higher than 9 and facultative alkaliphiles that can live both at neutral pH and alkaline conditions.
1) Metallotolearnt microorganisms are the microorganisms that are capable of tolerating and detoxifying high levels of dissolved heavy metals.
2) Most metallotolerant microorganisms tend to be acidophilic as the physiological activities of such microorganisms enable tolerance against high metal concentrations.
1) Radiophiles are a group of extremophiles that are capable of surviving extreme forms of radiations like ionizing radiant (gamma rays) and UV radiation.
2) Studies on radiophiles are quite limited as they are to be isolated from extreme environments like outer space of other planets.