33 Archaea Examples: Detailed Facts

Archaebacteria are the type of unicellular, autotrophic prokaryotes which can live in extreme conditions. These are the group of bacteria that belongs to extreme circumstances as they can grow in high temperature, low temperature with snow, high salinity, and highly acidic while some are also methane-producing and utilizing. Archaea examples are discussed below.

  1. Thermofilum pendens
  2. Thermoproteus tenax
  3. Thermoproteus neutrophillus
  4. Thermoproteus uzoniensis
  5. Vulcanisaeta distributa
  6. Vulcanisaeta moutnovskia
  7. Metallosphaera cuprina
  8. Metallosphaera sedula
  9. Staphylothermus hellenicus
  10. Staphylothermus marinus
  11. Thermosphaera aggregans
  12. Sulfolobus acidocaldarius
  13. Sulfolobus islandicus
  14. Desulfurococcus kamchatkensis
  15. Hyperthermus butylicus
  16. Thermus aqaticus
  17. Archaeoglobus fulgidus
  18. Archaeoglobus veneficus
  19. Archaeoglobus profundus
  20. Ferroglobus placidus
  21. Halalkalicoccus jeotgali
  22. halobacterium salinarum
  23. Haloferax volcanii
  24. Natrialba asiatica
  25. Methanobacterium bryantii
  26. Methanococcus  formicum
  27. Methanobrevibacter ruminantium
  28. Methanobrevibacter smithii
  29. Methanofollis liminatans
  30. Methanogenium cariaci
  31. Methanogenium organophilum
  32. Methanothermobacter thermautotrophicus
  33. Methanothermobacter thermoflexus
  34. Methanomicrobium mobile

The members of archea set an example for living life in extreme conditions. Mostly they are anaerobic. They possess unique cell membrane composition as they do not possess peptidoglycan as their cell wall building material. They also have different genetic composition matches with the eukaryotic nucleus.

Distribution Of Kingdom Archaea

Are you also interested in the unique characteristics of Archaebacteria?

They have unique cell membrane composition, as they lack peptidoglycan in their cell wall. They possess pseudomurein and the cell membrane is made up of ether-linked phospholipids chains. This gives them an adaptation to high temperatures and high salinity.

  • They have a specific genomic structure at the level of 16s ribosomal RNA nucleotides. This gives them an inbuilt resistance to some antibiotics like streptomycin & kanamycin.
  • They are obligate anaerobes as they follow different mechanisms for cell respiration. Like methanogens, they are the only living organism capable to perform methanogenesis i.e. production of methane gas during cellular respiration.

Domain archea:

All cells may be prokaryotic or eukaryotic. Procaryotes are the primitive, unicellular members of the kingdom Monera from Whitaker’s five kingdom classification, containing free genetic material in the cytosol while eucaryotes are having true nucleus and DNA is enclosed in a typical nuclear membrane, and possess other internal membranes. Approx 400 species have been reported in this domain to date.

Helpful archaea:

The first microorganism to thrive on earth was a thermoacidophile due to the environmental condition of the earth. Heat-loving, thermotolerant microorganism have their economic importance in multiple fields of science due to their ability to produce thermostable enzymes which can be used for biotechnological applications. It is generally associated with protein thermostability. Thus hyperthermophiles are best suited for this purpose as compared to mesophiles.

Why these are used?

  • Because they can easily break the hydrogen bonds and di-sulphide bridges with any conformational distortion in structure. 
  • Due to the usage of these bacterial generated enzymes, the risk of microbial contamination gets reduced.
  • It helps in increasing the diffusion coefficient and solubility of the compounds. It decreases the viscosity of the reaction medium.

One example of this is Thermus aquaticus– which now has been commercially utilised. The enzyme Taq polymerase was used as a thermostable enzyme in the Polymerase chain reaction for the amplification of DNA.

archaea examples
Image credit: NCBI
National Centre For Biotechnology Information

Crenarchaeota

Thermoacidophiles or thermophiles, are extremely heat-tolerant and inhabit near sulphur hot springs and moist regions. These organisms cannot live below the temperature of 1310 C. They possess a special protein in their cell wall as they can even resist 2300 F.

Thermophiles:

They are also known as thermoacidophiles because they can live at very high temperatures and can bear high acidic environments. They normally propagate at temperatures above 45 °C. They inhabit deep-sea hydrothermal vents, terrestrial hot springs, and other extreme geographical regions. Thermophilic archaea examples are:

  1. Thermofilum pendens
  2. Thermoproteus tenax
  3. Thermoproteus neutrophillus
  4. Thermoproteus uzoniensis
  5. Vulcanisaeta distributa
  6. Vulcanisaeta moutnovskia
  7. Metallosphaera cuprina
  8. Metallosphaera sedula
  9. Staphylothermus hellenicus
  10. Staphylothermus marinus
  11. Thermosphaera aggregans
  12. Sulfolobus acidocaldarius
  13. Sulfolobus islandicus
  14. Desulfurococcus kamchatkensis
  15. Hyperthermus butylicus
  16. Thermus aqaticus

Thermofilum pendens

This is a thermophilic, moderately acidic bacterium isolated from the Solfataric hot springs in Iceland. Like many other archaea, it seems to breathe sulfur and use peptides for energy. It has a very long thread-like structure up to 100 mm.

T. pendens dislikes ribulose-1,5-bisphosphate-carboxylase, AMP-phosphorylase, and ribose-1,5-bisphosphate-isomerase.

Thermoproteus tenax

They are hydrogen-sulfur autotrophs and can grow at temperatures up to 95 ° C. Thermoproteus has a unique membrane lipid that is an ether-bonded glycerol derivative of a branched lipid with 20 or 40 carbon atoms.

The cells are rod-shaped, up to 4 microns in diameter and up to 100 microns in length, and proliferate by forming branches at the ends of the cells and growing into individual cells.

Thermoproteus neutrophillus

These archaea can grow with elemental sulfur as terminal electron acceptors of energy metabolism. Sulfur-reducing microorganisms and methanogens have one thing in common. That is, both are alive at the expense of reduced S-S bonds.

The reduction of elemental sulfur is one of the most common properties of thermophilic and hyperthermophilic bacteria. Above pH 5, sulfide anions (HS) are nucleophiles that react with the elemental sulfur ring (S8) to form polysulfides (S42– and S52–). Above pH 7 and 75 ° C, elemental sulfur becomes imbalanced with thiosulfates and sulfides.

Thermoproteus uzoniensis

It is a hyperthermophilic rod-shaped archaeon found in hot springs and soil samples of Uzon Caldera. The cells are rods 1-20 μm long and 0.3-0.4 μm wide and may branch or have spherical protrusions at both ends. The cells do not move and lack flagella. Fermentation products are acetic acid, isobutyric acid and isovaleric acid.

Vulcanisaeta distributa

It is characterized by the worldwide distribution of hot springs and acidic hot springs. It is isolated from the hot springs of Owakiya, Kanagawa Prefecture. Acidic conditions (pH 3.5-5.6) are required for growth.

They are resistant to chloramphenicol, kanamycin, oleandomycin, streptomycin, and vancomycin but sensitive to erythromycin, novobiocin, and rifampicin.

Vulcanisaeta moutnovskia

This grows in the absence of archaeal cell extract in the medium. It is an anaerobic, heterotrophic, hyperthermophilic archaea that grow optimally at 85-90 ° C and pH 4.0-4.5.

This microorganism uses maltose, starch, malate, yeast extract, peptone, beef extract, casamino acid, and gelatin as carbon sources. It is a metabolically versatile archaeon that can ferment proteinaceous substrates and some sugars.

Metallosphaera cuprina

Originally isolated from the sulfur spring. It plays an important role in mobilizing metal sulfide deposits in the natural bioleaching environment. Metallosphaera is gaining interest in the biomine industry due to its ability to oxidize reduced inorganic sulfur compounds (RISCs) under high-temperature conditions.

Metallosphaera sedula

Thermophilic and rock autotrophic archaea, such as Metallosphaera sedula, occupy an acidic, metal-rich environment and are used in biomining processes. Their genome contains genes associated with autotrophic carbon fixation, metal resistance, and adhesion. Originally from the volcanic region of Italy.

It is used to decrease coal pyrite due to its ability to oxidize pyrite, known as depyritization. That is an obligate aerobe that grows best at 75 °C and pH 2.0

Staphylothermus hellenicus

It is a hyperthermophilic, heterotrophic organism that requires sulfur to grow. At low nutrient levels, it forms grape-like clusters up to 0.5-1.0 mm in diameter and 100 clusters high. It is isolated from a hydrothermal vent off the bay of Paleocoli on the island of Milos, Greece. Large cluster cells with diameters up to 15 μm are found at high vegetative levels.

Staphylothermus marinus

It Is a thermophile with a thermostable extreme enzyme that works especially at high temperatures. They are mostly sulfur-dependent and highly marine thermophiles. These archeons need sulfur to grow but can produce hydrogen if sulfur is limited. These extreme enzymes are used to convert sulfur to hydrogen sulfide. After that, hydrogen sulfide is released as waste.

Thermosphaera aggregans

It is hyperthermophilic, heterotrophic, strictly anaerobic and fermentative. They are firstly identified in the obsidian pool. They are coccoid in shape with multiple flagella. 

Thermosphaera - microbewiki
Thermosphaera aggregans
Image credit: Microbe wiki

Sulfolobus acidocaldarius

Sulfolobus excels in its ability to thrive at both high and low pH. The natural habitat of these organisms is the Solfatterfield around the world, including the United States, Russia, Japan, New Zealand and Iceland. They can grow optimally at 80 ° C and pH 2 with a terrestrial solfataric source.

Sulfolobus islandicus

The optimum temperature for proper growth varies between 75-80 C and ph ranges from 2.5-to 3.5. They can mostly be grown in sulphur-rich hot springs. As they are facultative autotrophs, can oxidize sulfur to sulfate while fixing carbon from carbon dioxide.

Desulfurococcus kamchatkensis

They are obligately anaerobic, hyperthermophilic, organotrophic archaeon isolated from a hot spring of Uzon Caldera. They require an optimum temperature range of 650-850 C with pH ranges between 5-7.

In the presence of sulfur as an electron acceptor, it undergoes sulfur respiration to produce H2S and CO2, but in the absence of sulfur, it undergoes peptide oxidation combined with hydrogen production to regenerate electron carriers.

Hyperthermus butylicus

This thermophilic archaeon uses H2S formation only as an assimilatory energy source. Its main form of energy is fermentation. It contains superoxide reductase and peroxiredoxin, which removes superoxide without producing O2.

Superoxide is lethal to living organisms due to its free radical state. Removing superoxide without producing O2 keeps the inner gradient relatively negative compared to the outer region.

Hyperthermus - microbewiki
Hyperthermus butylicus
Image credit: Microbe wiki

Thermus aqaticus

It is a thermophilic bacterium that grows at temperatures above 70 ° C and also has heat-resistant aminopeptidase activity. Bacterial growth is indicated by visible turbidity. These are organisms that enable PCR (polymerase chain reaction).

It feeds on organic materials produced by bacteria and other thermophiles, including some members of archaea. DNA polymerase was the first enzyme isolated from T.aquaticus that’s why also known as Taq polymerase.

Thermus aquaticus - Wikipedia
Thermus aqaticus
Image credit: Wikipedia

Euryarchaeota

Halophiles and methanogens both are lying under this category. Halophiles thrive in a high saline environment and methanogens are the only organism on the earth which can produce methane gas and are strictly anaerobic. They are mainly found in marshy land. Sometimes they are found in the intestinal tracts of ruminants.

1. Halophiles:

 Halophiles are the ones who can thrive in high saline or water conditions. They are considered a type of extremophile that can withstand extreme salt conditions in a variety of environments. Archaea are known to be the dominant group in this saline environment. Halophilic archaea examples are:

  1. Archaeoglobus fulgidus
  2. Archaeoglobus veneficus
  3. Archaeoglobus profundus
  4. Ferroglobus placidus
  5. Halalkalicoccus jeotgali
  6. halobacterium salinarum
  7. Haloferax volcanii
  8. Natrialba asiatica
  9. Natrialba magadii
  10. Natronomonas pharaonis
  11. Nitrosopumilus maritimus

Archaeoglobus fulgidus

Due to its hyperthermophilicity, it grows anaerobically at very high temperatures of 60-95 ° C and optimally at 83 ° C. They can create biofilms when exposed to environmental stresses such as extreme pH or temperature, high concentrations of metals, or high salt content.

Archaeoglobus veneficus

It is a hyperthermophilic archaeon found in the deep-sea hydrothermal vent. In addition, chemical organic nutritional growth is possible by reducing sulfate, sulfite, or thiosulfate. It is also a promising candidate for inexpensive and efficient purification of oil-contaminated environments due to its ability to degrade alkanes.

Archaeoglobus profundus

It is the mixotrophic anaerobe, oxidize aromatic compounds and lives at the temperature of 820C with a pH range of 4.5 to 7.5 and a concentration of NaCl between 0.9 and 3.6%. They use hydrogen as an electron donor.

Ferroglobus placidus

Ferroglobus placidus is an anaerobic, Fe (II) oxidizer. Iron, H2 and sulfides act as electron donors and NO3 is used as an electron acceptor. An interesting fact is that Fe (III) can be produced from Fe (II) under anoxic conditions. Interestingly, Fe (III) was formed in ancient rock, and Fe (II) was thought to have been oxidized by oxygen produced by cyanobacteria.

Halalkalicoccus jeotgali

It was isolated from shrimp-salted seafood. Extremely halophilic archaea (haloarchaea) are adapted to hypersaline environments and grow optimally in NaCl solutions of 2.6 M or higher.

Halobacterium salinarum

This is also known as Halobacterium cutirubrum or Halobacterium halobium. The membrane has a single lipid bilayer covered with a slime layer. They can generate an electrochemical proton gradient across the membrane by respiration and/or the light-driven proton pump bacteriorhodopsin.

Haloferax volcanii

Haloferax volcanii thrives in high salt environments. They promote salt crystallization by absorbing sunlight with a photosynthetic pigment known as carotenoids. It was first isolated from Dead Sea sediments.

Natrialba asiatica

They can live in extreme conditions, especially if they are capable to live in water saturated with salt. The genome encodes for many putative proteases/peptidases. Osmotic pressure and charged amino acids help to control the amount of salt in the cell.

Natrialba magadii

These are aerobic chemo-organotrophic, haloalkaliphilic archaeons that require alkaline conditions and high salt content for optimal growth. They required at least 2 M NaCl. They can grow between pH 7 and 10 with an optimum of 8.5.

Natronomonas pharaonis

It was isolated from an alkaline lake that had to deal with two extreme conditions: high salinity and an alkaline pH of 11. It grows optimally at 3.5M NaCl and pH 8.5. In contrast to other alkaliphiles, which use sodium Na+ instead of protons H+ as coupling ion between respiratory chain and ATP synthase, Natronomonas uses protons as coupling ion.

Nitrosopumilus maritimus

Ammonia-oxidizing archaea are ubiquitous in the marine and terrestrial environment and are now recognized as important contributors to the carbon and nitrogen cycle. This microbe was isolated from the bedrock of the Seattle Aquarium’s tropical basin.

2. Methanogens:

Methanogens act as a biocatalyst which occurs as an endogenous organism in many free-living marine organisms and anaerobic protozoa and is closely associated with hydrogenosomes, an organelle that produces H2, CO2, and acetate from the fermentation of high molecular weight substrates. The product of hydrogenosomes is a substrate for methane production. Methanogenic archaea examples are as follows:

  1. Methanobacterium bryantii
  2. Methanococcus  formicum
  3. Methanobrevibacter ruminantium
  4. Methanobrevibacter smithii
  5. Methanofollis liminatans
  6. Methanogenium cariaci
  7. Methanogenium organophilum
  8. Methanothermobacter thermautotrophicus
  9. Methanothermobacter thermoflexus
  10. Methanomicrobium mobile

Methanobacterium bryantii

Methanogens have an unusual requirement for Ni2+ which is a component of coenzyme F430 and hydrogenase and is necessary to prevent lysis of these organisms. Most organisms use carbon dioxide and hydrogen as an electron carrier. Autotrophic (acetoclastic) methanogens metabolize acetic acid to methane and carbon dioxide.

Methanobacteria - Wikipedia
Methanobacterium bryantii
Image credit: Wikipedia

Methanococcus  formicum

Methanogens are microorganisms that produce methane as a by-product of metabolism under hypoxic conditions. They are prokaryotes and belong to the archaeal domain. In marine sediments, the biological production of methane, also known as methane production, is generally limited to the decomposition of sulfates below the top layer.

Methanobrevibacter ruminantium

Methanobrevibacter ruminantium is an archaeon known to colonize the gastrointestinal tract of cattle and ruminants.

H2 is an important intermediate in the methanogenic decomposition of organic matter and acts as a reducing agent for methanogenic archaea to produce CH4, formate dehydrogenase is isolated from this bacterium and the enzyme uses F420 as the electron acceptor when formate is the substrate.

Methanobrevibacter smithii

It is a methanogen, a dominant, gram-negative, hydrogen-nutritive, archeon of the human gut that recycles hydrogen by combining it with carbon dioxide to form methane. The accumulation of hydrogen in the intestine reduces the efficiency and energy yield of microbial fermentation. As they an important role in removing excess free hydrogen.

Methanobrevibacter - Alchetron, The Free Social Encyclopedia
Methanobrevibacter smithii
Image credit: Alchetron

Methanofollis liminatans

This is an obligate anaerobe, mesophilic stain as gram-negative with peritrichous flagella. The optimum pH for growth is 7.0 i.e. neutral.  They are found in high-rate wastewater bioreactors or solfataric fields of Mount Tatio in the Atacama desert. As electron donors, they use 2-propanol, 2-butanol, ethanol, 1-propanol, and 1-butanol instead of H2. They need acetate as a carbon source for growth.

Methanogenium cariaci

Thermophilic coccoid methanogenic bacteria that grew optimally at about 55 °C were isolated from CO2 using 2-propanol as a hydrogen donor for methanogenesis. In addition, H2, formate or 2-butanol was used. They are strictly anaerobe, non-motile, gram-negative and found in marine and lake sediments that lack oxygen.

Methanogenium organophilum

It is strictly anaerobic and uses primary or secondary ‘OL’ groups as electron donors to reduce chemosynthetic nutrients, H2 , and in some cases formate, and carbon dioxide to methane. Optimal temperature range 15-35 ° C; Optimal pH 6.0-7.9.

Methanothermobacter thermautotrophicus

They are hyperthermophilic methanogens and were among the first microbes to have their complete genome sequenced. The main function of methanogens is to remove various fermentation products produced by other microorganisms and produce methane and CO2. Hydrogen reduction promotes an environment that promotes the growth of fermenting bacteria.

Methanothermobacter thermoflexus

They are also obligate anaerobes and can grow best between 550C-650C. In the absence of sulfates, metal oxide, and nitrites, methanogens consume these substrates and contribute to the anaerobic food chain in two different ways. First, methanogens catalyze the final stages of anoxic decomposition of organic matter to produce methane. Methane is released into the atmosphere. Second, it keeps the fermentation pathway energetically good by maintaining a very low H2 partial pressure.

Methanomicrobium mobile

Methanomicrobium mobile is considered to be the major methanogen in the lumen of humans and other castles. They produce methane by reducing carbon dioxide with hydrogen or formate. They are unable to metabolize acetate, methylamine or methanol.

Summary

I concluded my words with these lines that archaebacteria are the most primitive organism on this earth as they were the initiators of the living organism during “The Big Bang Theory”. When the temperature, pH, salinity and other climatic factors are at their extreme, at that time they are the one who survives. Members of Archae have the unique feature to thrive in any condition and sometimes they are exploited purposely by humans for their welfare.

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