Extremophiles Flashcards
Extremophiles
Environments where we do not usually find living organisms
How extremophiles survives
Extremozymes
Why study?
potential life on other planets, practical applications.
-Biocatalyst-
Range of extremity
Temp Chemical pH Salinity Pressure
Adaptation of extremophiles
Thrive in ecological niches e.g (no competition) sea vents hot springs soda lakes salt lakes
Industrial demand
Biocatalyst have better chemical precision than organic synthesis
3000 enzymes currently used in biotech.
Many enzymes cannot withstand industrial conditions
Types of extremophile - thermophile
widely studied
addapted to live at higher temp
can be used for glucose/fructose production
moderate thermophiles (45-60’c) paper bleaching
Thermophiles (65-85’c) - baking brewing detergents
Hypothermophiles (85’c +) - genetic engineering
How they survive?
Higher C-G base pairing (3H bonds)
Imparts resilience to heat by stabilising DNA
Proteins are strucutres differently
- increased surface charge
-increased core hydrophibicity
replacement of exposed thermolabile amino acid
Physchrophiles -type of extremophile
Temps of 15 to -15’c (least studied)
Variety - proteases, lipases, dehydrogenases
application
- detergents (cold wash)
- food industry (dairy/baking)
- cosmetics (perfumes)
- biosensors
Survival?
- Higher A-T base pair (2H bonds)
- Stable at low temperatures
- contains anti-freeze molecules in cells (ice formation)
Energy
- Chemoautothrophy - energy from chemical
- Heterotrophy - uses organic carbon (cant fix carbon)
High catalytic activity, low thermal stability
-may be explained for increased flexibility of molecule
Type of extremophile - Acidophiles
Thrive in < 2-3 pH
CUsed in amylase/glucoamylases
Proteases/cellulases -animal feel efficiency
oxidases - desulphurisation of coal
Microbe thrive in 0-1pH and synthesise sulfuric acid
Type of extrmophile - Alkaliphiles
> 9 pH
Preoteases and cellulase - detergents and food
Proteases, amylase and lipases that could be used in detergents at highly alkaline pH
Homology base PCR and activity screening used to identify target proteins.
Survival
- maintain cell at neutral pH
- most acidophiles pump protons out, extracellular proteins provide pH resistance- remove acid inside to extracellular environment
- higher acidic residues, amino acids are more acidic
- often binds to metal co-factor (???)
Type of extremophile - Halophiles
Love halogens (high salt content)
Extreme halophiles - up to 25% salt
-sea water (2%)
Wide spread - across all domains
- salt marshes
- salt deposits
- dry soils
- salted meats
- hypersalin sease and salt evaporation ponds
Survival -need salt to survive process - high salt content inside cell -increases osmolarity inside cell -e.ge amino acids, sugar -charged amino acids residue round cellular machinery which retains water Have: -low hydrophobicity -overexpressed acidic residues -lower number of helices, higher number of coil structures
Usual habitats
Bacillus species lives in nasal cavity of desert iguanas
salt glands that secret KCI brine during osmotic stress
Type of extremophiles - Piezophiles
High pressure (ocean floor) They are usually thermophiles, high and low temp reduce the membrane fluidity
Piezophiles have more unsaturated fatty acids
-prevents packing of cell membrane
Genes that upregulate to preserve protein folding and increase cellular respiration
Why study extremophiles
Enzymes that are
- tough in thermophiles
- efficient in psychrophiles
Enzymes from extremophiles may open up new industrial process
- High industrial heat/pH
- Inhibition by cold/salinity
Advantages
Cheaper than bioengineering enzymes from scrap
Extremophiles naturally engineered to work in extreme environments
