3. 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?
Life on other planets
Life at boiling temperatures
Applications are interesting
5. Extremophile
History
First suspected in 1950’s
Extensively studied since 1970’s
Temperature extremes
Boiling or freezing, 1000C to -10C
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
Psychrophiles - Low temperature
Arctic and Antarctic
1/2 of earth’s surface is oceans between
1-40C
Deep sea –10C to 40C
Most rely on photosynthesis
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
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”
15. What are enzymes?
Enzymes - 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-
de-natures (breaking the bonds that gives
a 3D shape)
https://www.youtube.com/watch?v=akhs3
wcSDGA
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
22. Thermophiles
Many industrial processes involve high heat
450C (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
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. 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
28. Diversity of Halophilic Organisms
Halophiles are a broad group & 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.
29. 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.
30. 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.
31. Osmoregulation
In order for cells to maintain their water
they must have an osmotic potential equal to
their external environment.
32. 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.
33. “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.
34. “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.
35. “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.
36. 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.
37. 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.
38. 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.
39. 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.
40. 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)
41. 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.
