Extremophiles are microbes that thrive in extreme environments like high temperatures, acidity, salinity, or freezing conditions. They have unique adaptations that allow them to survive where nothing else can. Their enzymes can withstand conditions like high heat, acidity, or salt that would destroy normal enzymes. These "extremozymes" have many biotechnology applications, like the thermophilic enzyme Taq polymerase that is crucial for PCR DNA amplification. The document discusses different types of extremophiles like thermophiles, psychrophiles, acidophiles, and halophiles, and their unique survival strategies and habitats. It also outlines how extremophile enzymes are used industrially, for example alkaline enzymes in deterg

1. Extremophiles
Life on edge
Life at High Temperatures, Thomas M. Brock

2. Extremophiles
Images from NASA, http://pds.jpl.nasa.gov/planets/
Extraterrestrial microbial
life-does it exist?

3. Lecture Aims
 What are Extremophiles- an introduction
 Strategies for growth & survival
 Biotechnology

4. Introduction to Extremophiles
 What are Extremophiles
 Live where nothing else can
 How do they survive?
 Extremozymes (more details later)
 Why are they are interesting?
 Extremes fascinate us
 Life on other planets
 Life at boiling temperatures
 Practical applications are interesting
 Interdisciplinary lessons
 Genetic Prospecting

5. Extremophile
 Definition - Lover of extremities
 History
 First suspected in 1950’s
 Extensively studied since 1970’s
 Temperature extremes
 Boiling or freezing, 1000
C to -10
C
 Chemical extremes
 Vinegar or ammonia (<5 pH or >9 pH)
 Highly saline, up to x10 sea water
 How we sterilize & preserve foods today

6. Extreme Temperatures
 Thermophiles - High temperature
 Thermal vents and hot springs
 May go hand in hand with chemical extremes
 Psychrophiles - Low temperature
 Arctic and Antarctic
 1/2 of earth’s surface is oceans between 1-40
C
 Deep sea –10
C to 40
C
 Most rely on photosynthesis

7. Thermophiles
Hydrothermal Vents- Black
smokers at 350 o
C
Obsidian Pool,
Yellowstone National Park

8. Psychrophiles

9. Chemical Extremes
 Acidophiles - Acidic
 Again some thermal vents & hot springs
 Alkaliphiles - Alkaline
 Soda lakes in Africa and Western U.S.
 Halophiles - Highly saline
 Natural salt lakes and manmade pools
 Sometimes occurs with extreme alkalinity

10. Acidophiles
pH 0-1 of waters
at Iron Mountain

11. Alkaliphiles
Mono Lake- alkaline
soda lake, pH 9 &
salinity 8%

12. Halophiles
Dead Sea
Great Salt Lake coastal
splash zones
Solar salterns Owens Lake

13. Survival
 Temperature extremes
 Every part of microbe must function at
extreme
 “Tough” enzymes for Thermophiles
 “Efficient” enzymes for Psychrophiles
 Many enzymes from these microbes are
interesting
Life at High Temperatures, Thomas M. Brock

14. Survival
 Chemical extremes
 Interior of cell is “normal”
 Exterior protects the cell

Acidophiles and Alkaliphiles sometimes excrete
protective substances and enzymes
 Acidophiles often lack cell wall
 Some moderate halophiles have high concs of a
solute inside to avoid “pickling”
 Some enzymes from these microbes are interesting

15. What are enzymes?
 Definition - a protein that catalyses (speeds
up) chemical reactions without being changed

16. What are enzymes?
 Enzymes are specific
 Lock and key analogy
Enzyme
Substrate A
Product B
Product C

17. What are enzymes?
 Activation energy
 Enzymes allow reactions with lower energy
Energy
Time
Without Enzyme
With Enzyme

18. What are enzymes?
 Enzymes are just a protein
 They can be destroyed by
 Heat, acid, base
 They can be inhibited by
 Cold, salt
 Heat an egg white or add vinegar to milk
 Protein is a major component of both-
denatures

19. Practical Applications
 Extremozymes
 Enzyme from Extremophile
 Industry & Medicine
 What if you want an enzyme to work
 In a hot factory?
 Tank of cold solution?
 Acidic pond?
 Sewage (ammonia)?
 Highly saline solution?

20. One solution
 Pay a genetic engineer to design a “super”
enzymes...
 Heat resistant enzymes
 Survive low temperatures
 Able to resist acid, alkali and/or salt
 This could take years and lots of money

21. Extremophiles got there first
 Nature has already given us the solutions
to these problems
 Extremophiles have the enzymes that
work in extreme conditions
Endolithic algae from Antarctica; Hot springs in Yellowstone National Pa
© 1998 Reston Communications, www.reston.com/astro/extreme.html

22. Thermophiles
 Most interesting, with practical applications
Many industrial processes involve high heat
 450
C (113F) is a problem for most enzymes
 First Extremophile found in 1972
Life at High Temperatures, Thomas M. Brock

23. PCR - Polymerase
Chain Reaction
 Allows amplification of small sample of DNA
using high temperature process
 Technique is about 10 years old
 DNA fingerprints - samples from crime scene
 Genetic Screening - swab from the mouth
 Medical Diagnosis - a few virus particles
from blood
 Thermus aquaticus or Taq
Life at High Temperatures, Thomas M. Brock

24. Psychrophiles
 Efficient enzymes to work in the cold
 Enzymes to work on foods that need to be
refrigerated
 Perfumes - most don’t tolerate high
temperatures
 Cold-wash detergents
Algal mats on an Antarctic lake bottom,
© 1998 Reston Communications, www.reston.com/astro/extreme.html

25. Acidophiles
 Enzymes used to increase
efficiency of animal feeds
 enzymes help animals
extract nutrients from feed
 more efficient and less
expensive
Life at High Temperatures, Thomas M. Brock

26. Alkaliphiles
 “Stonewashed” pants
 Alkaliphilic enzymes soften fabric and
release some of the dyes, giving worn look &
feel
 Detergents
 Enzymes dissolve proteins or fats
 Detergents do not inhibit alkaliphilic
enzymes

27. Halophiles
 What is a halophile?
 Diversity of Halophilic Organisms
 Adptation Strategies
 Osmoregulation-“Compatible Solute” Strategy
 “Salt-in” Strategy
 Interesting Facts and Applications

28. What is a halophile?
 Halophile = “salt loving; can grow in higher salt
concentrations
 Based on optimal saline environments halophilic
organisms can be grouped into three categories:
 extreme halophiles,
 moderate halophiles, and
 slightly halophilic or halotolerant organisms
 Some extreme halophiles can live in solutions of
25 % salt; seawater = 2% salt

29. Diversity of Halophilic Organisms
 Halophiles are a broad group &t can be
found in all three domains of life.
 Found in salt marshes, subterranean salt
deposits, dry soils, salted meats,
hypersaline seas, and salt evaporation
ponds.

30. Unusual Habitats
 A Pseudomonas species lives on a desert
plant in the Negev Desert- the plant
leaves secretes salt through salt glands.
 A Bacillus species is found in the nasal
cavities of desert iguanas- iguanas nasal
cavities have salt glands which secrete
KCl brine during osmotic stress.

31. Osmoregulation
 Halophiles maintain an internal osmotic
potential that equals their external
environment.
 Osmosis is the process in which water
moves from an area of high concentration
to an area of low concentration.

32. Osmoregulation
 In order for cells to maintain their water
they must have an osmotic potential equal to
their external environment.
 As salinity increases in the environment its
osmotic potential decreases.
 If you placed a non halophilic microbe in a
solution with a high amount of dissolved salts
the cell’s water will move into the solution
causing the cell to plasmolyze.

33. Osmoregulation
 Halophiles have adapted to life at high
salinity in many different ways.
 Structural modification of external cell
walls- posses negatively charged proteins
on the outside which bind to positively
charged sodium ions in their external
environments & stabilizes the cell wall
break down.

34. “Compatible Solute” Strategy
 Cells maintain low concentrations of salt in their
cytoplasm by balancing osmotic potential with
organic, compatible solutes.
 They do this by the synthesis or uptake of
compatible solutes- glycerol, sugars and their
derivatives, amino acids and their derivatives &
quaternary amines such as glycine betaine.
 Energetically synthesizing solutes is an expensive
process.
 Autotrophs use between 30 to 90 molecules of ATP to
synthesize one molecule of compatible solute.
 Heterotrophs use between 23 to 79 ATP.

35. “Salt-in” Strategy
 Cells can have internal concentrations that
are osmotically equivalent to their external
environment.
 This “salt-in” strategy is primarily used by
aerobic, extremely halophilic archaea and
anaerobic bacteria.
 They maintain osmotically equivalent
internal concentrations by accumulating
high concentrations of potassium chloride.

36. “Salt-in” Strategy
 Potassium ions enter the cell passively via
a uniporter. Sodium ions are pumped out.
Chloride enters the cell against the
membrane potential via cotransport with
sodium ions.
 For every three molecules of potassium
chloride accumulated, two ATP are
hydrolyzed making this strategy more
energy efficient than the “compatible
solute” strategy.

37. “Salt-in” Strategy
 To use this strategy all enzymes and
structural cell components must be
adapted to high salt concentrations to
ensure proper cell function.

38. Halobacterium: an extreme halophile
 Halobacterium are members of domain
archaea.
 Widely researched for their extreme
halophilism and unique structure.
 Require salt concentrations between 15% to
saturation to live.
 Use the “salt-in” strategy.
 Produce ATP by respiration or by
bacteriorhodopsin.

39. Halobacterium
 May also have halorhodopsin that pumps
chloride into the cell instead of pumping
protons out.
 The Red Sea was named after
halobacterium that turns the water red
during massive blooms.

40. Facts
 The term “red herring” comes from the
foul smell of salted meats that were
spoiled by halobacterium.
 There have been considerable problems
with halophiles colonizing leather during
the salt curing process.

41. Applications
 The extraction of carotene from carotene
rich halobacteria and halophilic algae that
can then be used as food additives or as
food-coloring agents.
 The use of halophilic organisms in the
fermentation of soy sauce and Thai fish
sauce.

42. Applications
 Other possible applications being explored:
 Increasing crude oil extraction (MEOR)
 Genetically engineering halophilic enzymes
encoding DNA into crops to allow for salt
tolerance
 Treatment of waste water (petroleum)

43. Conclusions
 Halophiles are salt tolerant organisms.
 They are widespread and found in all three
domains.
 The “salt-in” strategy uses less energy but
requires intracellular adaptations. Only a
few prokaryotes use it.
 All other halophiles use the “compatible
solute” strategy that is energy expensive but
does not require special adaptations.

44. Genetic prospecting
 What is it?
 Think of a hunt for the genetic gold

45. Summary
 Now you know something about Extremophiles
 Where they live & how they survive
 They are interesting because
 They have enzymes that work in unusual
conditions
 The practical applications are interesting