Karl Otto Stetter (born 16 July 1941) is a German

microbiologist A microbiologist (from Greek ) is a scientist who studies microscopic life forms and processes. This includes study of the growth, interactions and characteristics of microscopic organisms such as bacteria, algae, fungi, and some types of para ...

and authority on

astrobiology Astrobiology, and the related field of exobiology, is an interdisciplinary scientific field that studies the origins, early evolution, distribution, and future of life in the universe. Astrobiology is the multidisciplinary field that invest ...

. He is an expert on microbial life at high temperatures.

Career

Stetter was born in

Munich Munich ( ; german: München ; bar, Minga ) is the capital and most populous city of the German state of Bavaria. With a population of 1,558,395 inhabitants as of 31 July 2020, it is the third-largest city in Germany, after Berlin and ...

and studied

biology Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary ...

at the

Technical University of Munich The Technical University of Munich (TUM or TU Munich; german: Technische Universität München) is a public research university in Munich, Germany. It specializes in engineering, technology, medicine, and applied science, applied and Natural sci ...

. He wrote his doctoral dissertation on

lactobacilli The ''Lactobacillaceae'' are a family of lactic acid bacteria. It is the only family in the lactic acid bacteria which includes homofermentative and heterofermentative organisms; in the ''Lactobacillaceae,'' the pathway used for hexose fermentati ...

. From 1980 to 2002 he was professor at, and head of, the department of microbiology and of the

Archaea Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaeba ...

center of the

University of Regensburg The University of Regensburg (german: link=no, Universität Regensburg) is a public research university located in the medieval city of Regensburg, Bavaria, a city that is listed as a UNESCO World Heritage Site. The university was founded on 18 ...

. The majority of Stetter's research has focused on sampling, isolating and characterizing archaeal organisms which comprise the third

domain Domain may refer to: Mathematics *Domain of a function, the set of input values for which the (total) function is defined ** Domain of definition of a partial function ** Natural domain of a partial function **Domain of holomorphy of a function * ...

of life, particularly undiscovered extremely heat-loving (''hyperthermophilic'')

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

and

, also called

extremophile An extremophile (from Latin ' meaning "extreme" and Greek ' () meaning "love") is an organism that is able to live (or in some cases thrive) in extreme environments, i.e. environments that make survival challenging such as due to extreme tem ...

s, growing optimally between 80 and 113 °C.

Major discovery

In 1992, Stetter, along with

Robert Huber Robert Huber (; born 20 February 1937) is a German biochemist and Nobel laureate. known for his work crystallizing an intramembrane protein important in photosynthesis and subsequently applying X-ray crystallography to elucidate the protein's st ...

, discovered a new species of

thermophilic A thermophile is an organism—a type of extremophile—that thrives at relatively high temperatures, between . Many thermophiles are archaea, though they can be bacteria or fungi. Thermophilic eubacteria are suggested to have been among the earl ...

near

Kolbeinsey Ridge The Kolbeinsey Ridge is a segment of the Mid-Atlantic Ridge located to the north of Iceland in the Arctic Ocean. It is bounded to the south by the Tjörnes Fracture Zone, which connects the submarine ridge to the on-shore Northern Volcanic Zone ri ...

and named it '' Aquifex pyrophilous''. '' Nanoarchaeum equitans'', an archaeal microorganism containing the world's smallest known

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ...

, was discovered by Stetter in 2002 in a

hydrothermal vent A hydrothermal vent is a fissure on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hotspo ...

off the coast of

Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its ...

. This

archaebacterium Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaeba ...

was described in the scientific journal ''Nature'' in May 2002.

Discoveries

Among the other extremophiles discovered by Stetter has been ''

Pyrococcus furiosus ''Pyrococcus furiosus'' is a heterotrophic, strictly anaerobic, extremophilic, model species of archaea. It is classified as a hyperthermophile because it thrives best under extremely high temperatures, and is notable for having an optimum gr ...

'', which was found on the Italian island of

Vulcano Vulcano ( scn, Vurcanu) or Vulcan is a small volcanic island belonging to Italy in the Tyrrhenian Sea, about north of Sicily and located at the southernmost end of the seven Aeolian Islands. The island is known for its volcanic activity and ...

in 1981. This extremophile was the source of Pfu DNA polymerase. Stetter also discovered ''

Aquifex aeolicus "''Aquifex aeolicus''" is a chemolithoautotrophic, Gram-negative, motile, hyperthermophilic bacterium. "''A. aeolicus"'' is generally rod-shaped with an approximate length of 2.0-6.0μm and a diameter of 0.4-0.5μm. "''A. aeolicus''" is neither v ...

'' and ''

Aquifex pyrophilus ''Aquifex pyrophilus'' is a gram-negative, non-spore forming, rod-shaped bacteria. It is one of a handful of species in the Aquificota phylum, which are a group of thermophilic bacteria that are found near underwater volcanoes or hot springs. ...

''.

Awards and memberships

In 2003, Stetter was honored with the

Leeuwenhoek Medal The Leeuwenhoek Medal, established in 1877 by the Royal Netherlands Academy of Arts and Sciences (KNAW), in honor of the 17th- and 18th-century microscopist Antoni van Leeuwenhoek, is granted every ten years to the scientist judged to have made t ...

by the

Royal Netherlands Academy of Arts and Sciences The Royal Netherlands Academy of Arts and Sciences ( nl, Koninklijke Nederlandse Akademie van Wetenschappen, abbreviated: KNAW) is an organization dedicated to the advancement of science and literature in the Netherlands. The academy is housed ...

, an award given every 10 years to the scientist who has made the most outstanding contributions to the advancement of microbiology. Stetter is a member of the: *

Deutsche Akademie der Naturforscher Leopoldina The German National Academy of Sciences Leopoldina (german: Deutsche Akademie der Naturforscher Leopoldina – Nationale Akademie der Wissenschaften), short Leopoldina, is the national academy of Germany, and is located in Halle (Saale). Founded ...

*American Society of Microbiology (ASM) *Bayerische Akademie der Wissenschaften *Department of Microbiology and Molecular Genetics and Institute of Geophysics and Planetary Science (IGPP), UCLA *Deutsche Gesellschaft für Hygiene und Mikrobiologie (DGHM) *Gesellschaft Deutscher Chemiker (GDCh) *Gesellschaft Deutscher Naturforscher und Ärzte *Gesellschaft für Biologische Chemie (GBCh) *International Committee on Environmental Biogeochemistry (ISEB) *International Committee on Systematic Bacteriology (ICSB) *International Institute of Biotechnology
International Society for the Study of the Origin of Life (ISSOL)
*Royal Netherlands Academy of Arts and Sciences (1999) *Vereinigung für Allgemeine und Angewandte Mikrobiologie (VAAM)

References

External links