Archaebacteria: Definition, Characteristics, Structure, Classification & Examples

sinaumedia Literacy – In 1969 Robert H. Whittaker grouped living things into 5 kingdoms, namely Protista, Fungi, Monera, Animalia and Plantae.

This grouping is based on the arrangement of cells, levels of living things and how living things fulfill their food. Then this system was changed by splitting the kingdom Monera into the kingdom Archaebacteria and Eubacteria. Let’s get to know the archaebacterial kingdom closer to Sinaumed’s, along with the explanation.


Archaebacteria live in extreme environments that are thought to have been that of early Earth life. Archaebacteria or also called ancient bacteria because they are organisms whose typical energy metabolism forms methane gas (CH 4 ) by reducing carbon dioxide (CO 2 ).

Archaebacteria are anaerobic and chemosynthetic with cell walls that do not contain peptidoglycan, but their plasma membranes contain lipids. Living in an extreme environment. Archaebacteria consists of bacteria that live in critical or extreme places, for example bacteria that live in hot water, bacteria that live in places with high salt content, and bacteria that can live in hot or acidic places, such as in volcanic craters. , and on peatlands.

To find out more about various other types of bacteria as well as viruses and fungi, you can read the book Biology Encyclopedia Volume 2: Bacteria, Viruses & Protists, Fungi.


Archaebacteria can live in extreme places, such as hot springs with temperatures of 92ᴼC to nearly freezing places in Antarctica. Archaebacteria can also be found in places with very high acid or salt levels. Archaebacteria as unicellular organisms have the following characteristics, Sinaumed’s:

  • Size is about 1/10 micrometer to 15 micrometer.
  • Surviving in acid, salt water or alkaline environments, some can withstand pressures of over 200 atmospheres.
  • The cell membrane is composed of fat, in the form of ether bonds and isoprene units.
  • The cells are prokaryotic (do not have a nuclear membrane).
  • Lipids are branched in the cell membrane.
  • The cell wall consists of polysaccharides and proteins instead of peptidoglycan.
  • Do not have ER (Endoplasmic Reticulum), mitochondria, lysosomes and golgi bodies.
  • The ribosomes contain several types of RNA polymerase.
  • Archaebacteria contain nucleic acid in the form of RNA.
  • Reproduction by bud formation, binary fission and fragmentation.
  • Sensitive to diphtheria toxin.
  • Live in colonies (groups) and solitary (alone).
  • Some species of Archaebacteria have flagella for locomotion.
  • Most are anaerobic, but there are also several species that are aerobic, facultative anaerobes and obligate anaerobes.


The differences between eubacteria and archaebacteria mainly lie in their biochemical properties. For example, eubacteria have ester bonds in the lipid layer of the plasma membrane, while archaebacteria have bonds in the form of esters. The structure between Kingdom Eubacteria and Archaebacteria is almost the same. The only difference lies in the structural composition of the bacteria. The following is an overview of the structure of Sinaumed’s bacteria:

  • Flagella or Falgelum: Flagella as a filament that protrudes from the bacterial cell and consists of protein. Flagella act as a means of locomotion, but there are also bacteria without flagella that can move. Some types of bacteria have pili with structures like flagella, but shorter and thinner. Pili play a special role in transferring Genetime (DNA) molecules from one bacterium to another during conjugation events.
  • Capsule: Bacteria have a thick, viscous mucus that covers the cell wall. The capsule is made of polysaccharides and water, which helps the bacteria attach to surfaces or other bacteria. In general, capsules are bacteria that cause disease. Its function is as a means of defense and protection, to prevent drying out and as a food source for bacteria.
  • Cell Wall: Bacterial cell wall is a complex structure and functions as a shape determinant of the cell consisting of mucopolysaccharides and peptidoglycan which consists of large polymers of acetyl-N-acetyl linked together by covalent bonds. The difference between eubacteria and archaebacteria lies in the content of the cell wall.
  • Plasma Membrane: The plasma membrane is selectively permeable i.e. only certain molecules or substances can be transferred. Composed of layers of phospholipids and proteins. The plasma membrane regulates the exchange of substances between the cell and its environment and the formation of mesosomes.
  • Cytoplasm: Cytoplasm acts as the site of chemical reactions for the cell. Consists of 80% water, proteins, nucleic acids, fats, carbohydrates, inorganic ions, and chromatophores
  • Ribosomes: Ribosomes are formed in the form of smooth RNA and protein granules that contribute to the survival of bacteria during protein synthesis.
  • Chlorosome: Chlorosome is a structure beneath the plasma membrane, containing the pigment chlorophyll and other pigments that take part in photosynthesis. Usually found in certain bacteria, mostly archaebacteria.
  • Gas Vacuoles: Gas vacuoles allow bacteria to float on the surface of the water and get to light. Gas vacuoles are only owned by water bacteria that are photosynthetic.
  • Plasmids, namely circular DNA, can be inherited by carrying certain genes. Plasmids are in the cytoplasm.
  • Nuclear material (chromosomal DNA): DNA is the genetic material (carrier) called chromosomes or the nucleus of bacteria. The nuclear material plays an important role in regulating the processes occurring in the bacterial cell.
  • Mesosomes: Acts as an energy generator, is the center for the formation of new cell walls and cell division.
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Bacteria generally reproduce asexually. In addition, bacteria also reproduce by exchanging genetic material with other bacteria. This process of transferring genetic material is also known as parasexual or genetic recombination.

Bacterial growth, i.e. cell division in bacterial colonies, increases the number of colonies rapidly. Factors that affect reproduction, including temperature (optimal temperature – 300°C), humidity (bacteria grow well in a humid environment), sunlight (inhibits bacterial growth because it destroys the bacterial chromosome structure), chemicals (damages or kills bacterial cell wall and inhibits bacterial growth).

Availability of food reserves and metabolic waste (decreased food reserves in the medium and the appearance of bacterial waste metabolism inhibits the growth of bacterial colonies). Archebacteria reproduce through binary fission, multiple fission, bud formation, and fragmentation, as explained by Sinaumed’s:

Binary Split

In binary fission, bacteria divide directly from one cell to two cells, four cells, eight cells, sixteen cells, and so on.

Bud Formation

Bud formation (Cyanophyta or blue-green algae): Bacteria form buds in the form of twigs and eventually precipitate to form new bacteria. It can be found in the Sreptomycetaceae family.


Fragmentation (Cyanophyta or blue-green algae): Fragmentation is the breaking off of body parts that can form new individuals. Common in algae in the form of threads, and can be found in the Sinaumed’s oscillator.

Transfer of Genetic Material in archabacteria bacteria, including through:

  • Connection or Conjugation: Conjugation is a way of sexual reproduction in organisms that are not yet known to men and women. Conjugation of bacteria can be carried out when two bacterial cells with different exposures are close together, forming and attaching to conjugated tubes (connecting vessels) so that genetic material (DNA) and cytoplasm can pass from one cell to another. Next, in the recipient cell, the DNA is combined (genre combination) between the donor cell DNA and the recipient cell DNA, followed by cytoplasmic incorporation (plasmogamy). After the process of dividing the nucleus in the receiving cell, the next process is binary, and the cell divides again in two.
  • Transformation: Transformation is the process of transferring genetic material in the form of DNA or just one gene to another bacterium by a complex physiological process. The transformation is usually carried out by Rhizobium, Bacillus, Stretococcus pneumoniae and Neisseria gonorrhoeae.
  • Transduction: Transduction is the transfer of bacterial genetic material to other bacteria by viral intermediaries.


Archaebacteria include autotrophic and heterototrophic organisms. The types of Archaebacteri are as follows.. Thermo-acidophilic bacteria Halobacterium Metagen bacteria. Kingdom Archebacteria is further grouped into 5 phyla, namely:


Crenarchaeota, commonly found in marine environments. Crenarchaeota include hyperthermophiles, thermophiles, and thermoacidophiles.


Euryarchaeota are the part that is often studied and most of them are included in the halophiles and methanogenic bacteria.


The Thaumarchaeota include the ammonia-oxidizing archaea and those known to metabolize energy.


Nanoarchaeota, this phylum has a single representative member, namely nanoarchaeum equitans.


Korarchaeota, consisting of hyperthermophiles found at high ambient temperatures.

Archaebacteria Group Based on Metabolism and Habitat

Archaebacteria are also grouped based on their metabolism and habitat. The following is a group of archaebacteria along with examples.


Methanogens: a group of Archaebacteria that reduce carbon dioxide (CO 2 ) to water (H 2 O) and methane (CH 4 ) using hydrogen (H 2). Methanogens are chemosynthetic and anaerobic. Its habitat is in swamps, mud and places with little oxygen. There are also several species that live and live in symbiosis in the stomach or digestive tract of ruminant animals, such as termites, cows, and other herbivores that rely on cellulose for food. Methanogens have an important role in nutrition. An example is Succinomonas amylolytica as a starch breaker in the digestion of cows. In addition, methanogens also act as decomposers, so they can be used in animal waste processing to produce methane gas, which is an alternative fuel. Methanogens get food by decomposing the remains of dead plants, then produce methane gas. This type of bacteria is capable of producing CH 4 methanefrom the oxidation of H2 and CO2 , for example:

  • Lachnospora multiporus: These organisms break down and simplify pectin
  • Succumonas amylotica: Has the ability to break down aluminum
  • Ruminococcus albus: This organism is capable of hydrolyzing cellulose by breaking down cellulose
  • Methanococcus janashi: Is a producer of methane gas

Extreme thermophiles

Extreme thermophiles (thermoacidophilic): Extreme thermophiles (thermoacidophilic) are a group of Archaebacteria organisms whose habitat is in an acidic and hot environment, can live at a maximum temperature of 60-80ᴼC. Thermoacidophiles live by oxidizing water containing sulfur and are near hydrothermal vents in the ocean below.

Thermoacidophilic is the Archaebacteria group closest to eukaryotic organisms. Sulfolobus sp is a thermoacidophilic organism that lives in sulfur hot springs in Yellowstone National Park (United States of America). Sulfolobus sp lives by oxidizing sulfur to get energy. This group is also called thermoacidophiles, because they like acid and heat. Another Archaebacteria organism, namely Thermus aquaticus, lives in water with a temperature of 105ᴼC near hydrothermal vents in the deep sea (underwater volcanic craters).

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Examples of thermoacidophiles are: Thermoproteus tenax, Thermoplasma acidophilum, Humicola insolens, Chaetomium thermophilum, Thermomyces lanuginosus, Brevibacillus levickii, Thermoascus aurantiacus and Sulfolobus yangmingensis.

Extreme Halophile

Extreme halophile (halophilic): The term Halophile comes from two Greek words, namely ‘halo’ which means salt and ‘philos’ which means lover. Extreme halophiles (halophiles) are a group of Archaebacteria that live in salty places with high salt levels, such as the Dead Sea and the Great Salt Lake (salt lake in America). Halophiles are heterotrophs. To produce energy, halophiles carry out aerobic respiration, some can photosynthesize.

Examples of extreme halophiles: Genus Halobacterium, Halobacterium, Halococcus, Halogeometricum borinquense, Haloferax volcanii, Haloterrigena turkmenica, Halococcus dombrowskii, Halorubrum kocurii, Halobacterium salinarum, Haloarcula marismortui and others.

Sulfur Reduction

Sulfur reducers: Like methanogens, sulfur reducers live near volcanic vents and swimming pools. They use the abundant inorganic sulfur which is often found near the vents along with hydrogen as food. They also have a very high heat tolerance, so they can live in temperatures up to 85 degrees Celsius.

There are also various kinds of enteric bacteria and mucous membranes that we can encounter in everyday life which you can learn about in Bacteriology book 2 Textbook of Health Analysts.


Archaebacteria are organisms whose typical energy metabolism forms methane gas (CH4) by reducing carbon dioxide (CO2). Archaebacteria are anaerobic and chemosynthetic. The name “archaebacteria,” with its prefix meaning “ancient,” as well as the fact that most of the Monera were discovered at the time of primitive Earth led many to believe that archaebacteria may have been the earliest forms of life on this planet. Archaebacteria benefits for human survival, including:

  • Several archaebacteria enzymes in the food industry are useful for converting cardiac starch into dextrins (a type of carbohydrate). For example: A. oryzae, Aspergillus niger, A. niger, Bacillus coagulans.
  • Archaebacteria enzymes are added to detergents or laundry soap to increase their ability to withstand high pH and temperatures. For example: Streptococcus bovis, Bacillus stearothermophilus and B.Lactobacillus plantarum.
  • As a producer of biogas for alternative fuels.
  • Several species of archaebacteria are used to deal with pollution, for example oil spills. Examples: Achromobacter (Alcaligenes), Pseudomonas, Arthrobacter and Acinetobacter.

Not all of the bacteria in the world can be harmful to humans or animals. But there are also bacteria that can help human survival. The book Everything About Bacteria and Viruses that is below will explain the various types of bacteria that exist in the environment.


However, there are also archaebacteria that are detrimental to humans, namely Archaebacteria, which can damage food preserved in salt and cause rapid decomposition of marine fish. In addition, harmful bacteria can also cause disease. You can see this in the book Bacteriology: Microorganisms that Cause Infection below.

Tackling food spoilage bacteria that can be done, among others, by preserving and processing food. Meanwhile, tackling bacteria that cause disease is carried out by maintaining cleanliness and health, as well as immunization. Here’s the explanation:

  • Food Preservation and Processing: Food preservation and processing is an effort to make food conditions not easily damaged by microorganisms, such as bacteria. Food that is preserved and processed makes it not an optimum place for bacteria to live. Food preservation is carried out by means of sweetening, drying, smoking, pickling, salting and cooling. For example: crackers, smoked meat, pickles, salted fish, candied fruit and sale. Food processing by heating can kill most of the disease-causing microorganisms found in food and beverages. Forms of heating food and drinks can be done by cooking as usual or in a special way. e.g. pasteurization or sterilization.
  • Maintain Personal and Environmental Hygiene and Health: Diseases caused by microorganisms arise due to a way of life that lacks cleanliness. Disease is also easier to attack people who are physically weak, this causes the need for efforts to maintain cleanliness and health in order to avoid various kinds of diseases. Efforts that can be made to maintain cleanliness and health include the following: keeping the environment clean, maintaining body hygiene by bathing and washing hands before eating, doing regular exercise, eating nutritious food, getting enough rest.
  • Immunization: As an effort to gain immunity against diseases caused by microorganisms, such as bacteria. Immunization stimulates a person’s immunity by administering weakened pathogenic microorganisms. Immunization is also called vaccination or vaccine administration. Examples of vaccines to prevent diseases caused by bacteria are as follows: Cholera vaccine to prevent cholera. Typhus vaccine to prevent typhus. BCG vaccine to prevent TB disease. DPT vaccine to prevent diphtheria, pertussis or cough and tetanus.

Thus the definition, characteristics, body structure, reproduction, classification, benefits and negative impacts of archaebacteria in everyday life. Hope this is useful Sinaumed’s, enjoy learning!