Psychrophiles are cold-loving microorganisms that can survive and grow in extremely cold environments like polar regions and glaciers. They have adapted mechanisms like maintaining membrane fluidity through unsaturated fatty acids and proteins that preserve RNA structures at cold temperatures. Psychrophiles possess enzymes that remain active at low temperatures through higher alpha-helix content and compounds like trehalose that prevent protein denaturation. Their adaptations allow psychrophiles and their cold-active enzymes to have applications in various industries like detergents, food processing, and bioremediation.
2. Extremophiles are organisms that can survive in
extreme environmental conditions.
Extremophiles include members of all three domains
of life, i.e., bacteria, archaea, and eukarya.
Although the molecular strategies employed for
survival in such environments are still not fully
clarified, it is known that these organisms have
adapted biomolecules and peculiar biochemical
pathways to adapt in extreme environments.
They possess enzymes and proteins which remain
catalytically active under extremes of temperature,
salinity, pH, and solvent conditions.
3. Psychrophiles are cold- loving organisms that grow
at temperature of 15° C or lower.
Psychrotolerant organisms are able to grow at
temperature close to the freezing point of water but
fastest growth rate at above 20° C.
4. Habitat:
Microorganisms are found inhabiting the low
temperature environments of the Earth, including
polar regions, glaciers, ocean deeps, snow covered
regions, shallow subterranean regions, upper
atmosphere, refrigerated appliances and on and in
plants and animals inhabiting cold regions.
Examples: Pseudomonas antarctica, Psychrobacter
aquaticus
5. Adaptation Mechanism of Psychrophile
Maintaining membrane fluidity- Unsaturated-cis-
Fatty acid, Carotenoids- prevent freezing.
Cold shock proteins (CSPs) & Cold acclimatization
proteins (CAPs) are cold adaptive proteins present in
psychrophiles. These small proteins bind to RNA and
preserve its single-stranded conformation.
Antifreeze proteins, Ice nucleating protein, and
Compatible osmotic solutes- protect the cell from
freezing.
6. Proteins have a higher content of α-helix relative
to the β-sheets.This helps to maintain flexibility
even at low temperatures.
Trehalose and exopolysaccharides (EPSs)- plays
an impoertant role in cryoprotection. It also prevent
protein denaturation and aggregation.
7. Application
Detergent, textile, food, pharmaceutical, leather,
brewing and wine, paper and pulp industries.
The use of psychrophiles and their enzymes are
proposed in the bioremediation of soils and waste
waters, as an alternative to physiochemical
methods.
