Émile Duclaux (24 June 1840 – May 2, 1904) was a French

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 par ...

and

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of ...

born in Aurillac,

Cantal Cantal (; or ) is a rural Departments of France, department in the Auvergne-Rhône-Alpes Regions of France, region of France, with its Prefectures in France, prefecture in Aurillac. Its other principal towns are Saint-Flour, Cantal, Saint-Flou ...

. He studied at the College of Aurillac, the Lycée Saint-Louis in

Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of ci ...

and at

École Normale Supérieure École or Ecole may refer to: * an elementary school in the French educational stages normally followed by Secondary education in France, secondary education establishments (collège and lycée) * École (river), a tributary of the Seine flowing i ...

. In 1862 he began work as an assistant in the laboratory of

Louis Pasteur Louis Pasteur (, ; 27 December 1822 – 28 September 1895) was a French chemist, pharmacist, and microbiologist renowned for his discoveries of the principles of vaccination, Fermentation, microbial fermentation, and pasteurization, the la ...

(1822–1895). During his career, he taught classes in

Tours Tours ( ; ) is the largest city in the region of Centre-Val de Loire, France. It is the Prefectures in France, prefecture of the Departments of France, department of Indre-et-Loire. The Communes of France, commune of Tours had 136,463 inhabita ...

(1865),

Clermont-Ferrand Clermont-Ferrand (, , ; or simply ; ) is a city and Communes of France, commune of France, in the Auvergne-Rhône-Alpes regions of France, region, with a population of 147,284 (2020). Its metropolitan area () had 504,157 inhabitants at the 2018 ...

(1866),

Lyon Lyon (Franco-Provençal: ''Liyon'') is a city in France. It is located at the confluence of the rivers Rhône and Saône, to the northwest of the French Alps, southeast of Paris, north of Marseille, southwest of Geneva, Switzerland, north ...

(from 1873) and

(from 1878). In Paris, he was a professor of

meteorology Meteorology is the scientific study of the Earth's atmosphere and short-term atmospheric phenomena (i.e. weather), with a focus on weather forecasting. It has applications in the military, aviation, energy production, transport, agricultur ...

at the Institute of

Agronomy Agronomy is the science and technology of producing and using plants by agriculture for food, fuel, fiber, chemicals, recreation, or land conservation. Agronomy has come to include research of plant genetics, plant physiology, meteorology, and ...

. For much of his career he was associated with the work of Louis Pasteur. In 1888 he was elected to the ''

Académie des sciences The French Academy of Sciences (, ) is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French Scientific method, scientific research. It was at the forefron ...

'', and in 1894 became a member of the '' Académie Nationale de Médecine''. Duclaux's work was largely in the fields of

chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...

bacteriology Bacteriology is the branch and specialty of biology that studies the Morphology (biology), morphology, ecology, genetics and biochemistry of bacteria as well as many other aspects related to them. This subdivision of microbiology involves the iden ...

hygiene Hygiene is a set of practices performed to preserve health. According to the World Health Organization (WHO), "Hygiene refers to conditions and practices that help to maintain health and prevent the spread of diseases." Personal hygiene refer ...

and

agriculture Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...

. Duclaux initiated the custom of naming enzymes by adding the suffix "

-ase The suffix -ase is used in biochemistry to form names of enzymes. The most common way to name enzymes is to add this suffix onto the end of the substrate, ''e.g.'' an enzyme that breaks down peroxides may be called peroxidase; the enzyme that pr ...

" to the enzyme's substrate. His intention was to honor the first scientists (namely Anselme Payen, 1795–1871; and Jean-François Persoz, 1805–1868) to isolate an enzyme; "

diastase A diastase (; from Greek διάστασις, "separation") is any one of a group of enzymes that catalyses the breakdown of starch into maltose. For example, the diastase α-amylase degrades starch to a mixture of the disaccharide maltose; the ...

", in 1833.Émile Duclaux (1899) ''Traité de Microbiologie'', vol. 2. Paris, France: Masson and Co. See Chapter 1, especiall
p. 9
With Pasteur, he collaborated in the study of

silkworm ''Bombyx mori'', commonly known as the domestic silk moth, is a moth species belonging to the family Bombycidae. It is the closest relative of '' Bombyx mandarina'', the wild silk moth. Silkworms are the larvae of silk moths. The silkworm is of ...

diseases, and also took part in experiments to debunk the theory of

spontaneous generation Spontaneous generation is a superseded scientific theory that held that living creatures could arise from non-living matter and that such processes were commonplace and regular. It was hypothesized that certain forms, such as fleas, could ...

. In the 1870s, he undertook studies of

phylloxera Grape phylloxera is an insect pest of grapevines worldwide, originally native to eastern North America. Grape phylloxera (''Daktulosphaira vitifoliae'' (Fitch 1855) belongs to the family Phylloxeridae, within the order Hemiptera, bugs); orig ...

, an aphid-like pest that plagued

grape vine ''Vitis'' (grapevine) is a genus of 81 accepted species of vining plants in the flowering plant family Vitaceae. The genus consists of species predominantly from the Northern Hemisphere. It is economically important as the source of grapes, bot ...

yards. In addition, he performed research on the composition of milk, and conducted studies on beer and wine. In 1887 he began publication of the ''Annales de l'Institut Pasteur'', with Charles Chamberland (1851-1908), Jacques-Joseph Grancher (1843–1907), Edmond Nocard (1850–1903) and Pierre Paul Émile Roux (1853–1933) as members of the first editorial board. Following Pasteur's death in 1895, Duclaux became director of the Institute, with Roux and Chamberland serving as its sub-directors. Duclaux was a prolific writer, some of his better known publications were ''Traité de microbiologie'', ''L'hygiène sociale'', ''Ferments et maladies'' and ''Pasteur, histoire d'un esprit'', the latter being a biography dedicated to Pasteur. Being actively involved in French politics, he was a vocal supporter of

Alfred Dreyfus Alfred Dreyfus (9 October 1859 – 12 July 1935) was a French Army officer best known for his central role in the Dreyfus affair. In 1894, Dreyfus fell victim to a judicial conspiracy that eventually sparked a major political crisis in the Fre ...

(1859-1935), when the latter was unjustly accused of treason. Duclaux's second wife, Agnes Mary Frances Duclaux (maiden name Agnes Mary Frances Robinson 1857–1944), was a well-known author, and his son, Jacques Eugène Duclaux (1877–1978), was a highly regarded chemist.

References

External links

Biography of Emile Duclaux
Pasteur Brewing *

(chronological biography) {{DEFAULTSORT:Duclaux, Emile 1840 births 1904 deaths People from Aurillac 19th-century French biologists French microbiologists Hygienists Members of the French Academy of Sciences Lycée Saint-Louis alumni