Extremophiles are organisms that thrive in physically and chemically extreme conditions that are detrimental to most life on Earth, such as high temperatures, pressures, or pH levels. They produce enzymes called extremozymes that remain active under extreme conditions. Extremophiles are mainly single-celled organisms from the Archaea domain and are classified based on the extreme conditions they can tolerate, such as high heat (thermophiles and hyperthermophiles), low temperatures (psychrophiles), high salt concentrations (halophiles), or acidity/alkalinity (acidiphiles and alkaliphiles). The enzymes and biomolecules extremophiles produce can be useful for industrial applications.

2. Extremophiles :-
An organism that thrives in physically &
geochemically in extreme conditions that are
detrimental to most of life on earth .
Extreme conditions such as high temperature , high
pressure or extreme Ph .
The enzymes produced by these are called
extremozymes which remain active in extreme
conditions when other normal enzymes typically
failed .
Mainly belongs to archea domain .
Mostly single celled .

3. CLASSIFICATION OF EXTREMOPHILES
Based on temperature :-
Thermophiles :-
Lives at temperature b/w 45 - 80°c.
Eg:- rhizomucor pusillus .
Hyperthermophiles :-
Lives at temperature above 80°c .
Found in hypothermal system .
Eg:- pomii worm usually found at hydrothermal vent
in pacific ocean .
Thermus aquaticus

4. Psychrophiles / cryophile :-
Organism that reproduced and growth best at low
temperature typically in range of -10°c - 20°c .
Psychrophiles posses enzymes that are adopted to
function at low temperature & denaturate at
moderate temperature .
Eg:- snow field algae , polaromonas vacuolate

6. Based on Ph :-
Acidiophile :-
an organism at optimal growth at pH level of 3 or
below 3 .
They have evolved efficient mechanism that pumps
protons out of then intracellular space to keep
cytoplasm at neutral pH .
They are hard to grow in laboratory cultures .
Eg:- acetobacter sps .
Alkaliphiles :-
An organism with optimal growth at pH level of 9 or
above 9 .
Eg:-bacillus okhensis

7. Halophiles :-
Live in environment with high salt concentration .
Requiring at least (0.2M) concentration of salt
(NaCl) for growth usually bac and algae
Environments
hyper saline lakes(dead sea)
salt marshes
EX:- duniella salina
halophilic algae that lives in inland seas ,
saline lakes and salt marshes
Harvested for antioxidant content in carotene and
glycerol
Used in cosmetics and dairy supplements

8. Mechanism of survival :-
Influx of potassium ions into cytoplasm
Organic compounds accumulated in cytoplasm can
synthesize or pulled from environment
Xerophiles:-
Grow in extremely dry, desiccating conditions
The organism live in desert are characterized by low
moisture and high acidity
 EX:- cacti, mold, yeast

9. Barophiles /piezophiles:-
Lives optimally at high pressure such as ocean or
under ground
Deep under the earth or water
They have tough cell wall and porins
They have ability to metabolize many different
nutrients
EX:- pseudomonas

10. Radio resistant :-
Resistant to high levels of ionizing radiation mostly
UV, nuclear radiation
EX :- clostridium
radiodurans
deinococcus
Metallotolerent
Capable of tolerating high levels of dissolved heavy
metals in solution such as Co, Cd, Ar, Zn
EX :- ferroplasma sps
cupriavidus metallidurans

11. Osmophiles:-
 Capable of growth in environment with high sugar
conc
Oligothrophs:-
Capable of growth in nutritionally limited
environments
Cryptoenodilith/ endolith:-
Lives in microscopic spaces with in rocks , pores
between aggregative grains
Hypoliths:-
Lives in underneath rocks in cold deserts

12. Lithoautotrophs:-
These organisms are capable of deriving energy
from reduced mineral compounds like pyrites and
are active in geochemical cycling and weathering of
parent bed rock to form soil
The source of carbon is co2
Polyextremophiles:-
Organism that qualifies as extremophile under
more than one category
Ex :-radiodurans capable living in radioactive
environment , extreme cold, dehydration, vacuum ,pH

13. BIOTECHNOLOGICAL APPLICATIONS