Biography of Louis Pasteur – French Biologist and Chemist

renowned for his discovery of the principles behind vaccines, fermentation of microbial substances and pasteurization.

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This article writter by MN Editors on November 23, 2021

Microbiology Notes is an educational niche blog related to microbiology (bacteriology, virology, parasitology, mycology, immunology, molecular biology, biochemistry, etc.) and different branches of biology.

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Biography of Louis Pasteur - French Biologist and Chemist
Biography of Louis Pasteur - French Biologist and Chemist
Known For Discovered pasteurization, studies of anthrax, rabies, improved medical techniques
Born December 27, 1822 in Dole, France
ParentsJean-Joseph Pasteur and Jeanne-Etiennette Roqui
DiedSeptember 28, 1895 in Paris, France
EducationCollège Royal at Besancon (BA, 1842; BSc 1842), Ecole Normale Supérieure (MSc, 1845; Ph.D. 1847)
SpouseMarie Laurent (1826–1910, m. May 29, 1849)
ChildrenJeanne (1850–1859), Jean Baptiste (1851–1908), Cécile (1853–1866), Marie Louise (1858–1934), Camille (1863–1865)

Louis Pasteur (December 27, 1822 – September 28th 1895) was a French microbiologist and chemist who was renowned for his discovery of the principles behind vaccines, fermentation of microbial substances and pasteurization. His studies in chemistry led to astonishing breakthroughs in study of causes as well as preventatives of illnesses, and created the basis for hygiene, public health , and many aspects of modern medical practices. His work is credited with saving the lives of millions through the development of vaccines to treat anthrax and rabies. He is recognized as one of the pioneers of modern bacteriology. He’s been honored by the title of “father of bacteriology” and as the “father of microbiology” (together with Robert Koch, and the later epithet is can also be was attributed to Antonie van Leeuwenhoek).

Contributions of Louis Pasteur in brief

Pasteur was the one who disproved the theory that spontaneous generations can occur. Under the auspices the French Academy of Sciences, his research proved that when sealed and sterilized flasks, there was no growth or grew. In contrast in open, sterilized flasks, microorganisms can develop. For his work the academy granted to him an Alhumbert Prize carrying 2,500 francs in 1862.

Pasteur is also thought of as one of the earliest proponents of the germ theory of disease which was considered to be a secondary notion in medicine at the time. His numerous experiments proved that disease could be prevented through the killing or eradication of germs which directly supported this germ theory as well as its applications in the field of clinical medical practice. The most famous of his work is the public at large for his development of the method to treat wine and milk to prevent bacterial contamination which is now known as pasteurization.

Pasteur also made important discoveries in chemistry, the most specifically on the molecular foundation for the asymmetry in certain crystals as well as racemization. At the beginning of his career his study of tartaric acid led to the first understanding of what is now known as optical isomers. His work led to the present understanding of the fundamental principle that governs the organic structure.

He was head for Pasteur Institute from 1887. Pasteur Institute, established in 1887. Pasteur died in 1887, and his remains were buried in a vault under the institute. While Pasteur created groundbreaking experiments however, his name was linked to various controversy. An examination of his notebook in the past revealed that he used deceit to thwart his rivals.

The early life of Louis Pasteur

Louis Pasteur was born on 27 December 1822 at Dole, Jura, France to an Catholic family with an unemployed tanner. He was the son from Jean-Joseph Pasteur and Jeanne-Etiennette Roqui. The family relocated into Marnoz in 1826 before moving relocated to Arbois around 1827. Pasteur began primary school in 1831.


He was a typical student during his first days, but not very academically inclined since his hobbies included fishing and sketching. He sketched many pastels as well as portraits of his family, friends, and neighbors. Pasteur was a student at secondary school in The College d’Arbois.] On October 18, 1838 Pasteur left in Paris in order to be a member of the Pension Barbet, but became homesick and returned in the month of November.

He graduated in 1839. was admitted to at the College Royal at Besancon to pursue a degree in philosophy. He graduated with a Master of Letters degree in 1840. The college appointed him a tutor at Besancon college, while pursuing an advanced science degree course that included particular mathematics. He failed his initial test in 1841. He did pass the baccalaureat scientific (general scientific) degree at Dijon which was where he received the Bachelor of Science in Mathematics degree (Bachelier Sciences Mathematiciques) in 1842, however, with a poor score in Chemistry.

In the year 1842 Pasteur completed the entry examination to the Ecole Normale Superieure. He passed the initial test, but because of his score, Pasteur decided not to take the test again and to try it the following year. He returned at the Pension Barbet to prepare for the test. He also took courses at Lycee Saint-Louis and lectures of Jean-Baptiste Dumas at the Sorbonne.

The year was 1843. He cleared the test with a top score and was admitted to in the Ecole Normale Superieure. In 1845, he earned the degree of licencie-es-sciences. Then, in 1846, he became a professor of Physics in the College de Tournon (now called Lycee Gabriel-Faure) in Ardeche. However, the chemical chemist Antoine Jerome Balard wanted him to return to the Ecole Normale Superieure as a graduate laboratory assistant (agrege preparateur). The chemistry graduate joined Balard and also began his crystallography research and at the age of 1847, defended two of his thesis, one in chemistry, the other one in Physics.The thesis was (a) Chemical Thesis “Recherches sur la capacite de saturation de l’acide arsenieux. Etudes des arsenites de potasse, de soude et d’ammoniaque. “; (b) Physics Thesis: “1. Etudes des phenomenes relatifs a la polarisation rotatoire des liquides. 2. Application de la polarisation rotatoire des liquides a la solution de diverses questions de chimie.”

After a brief time as the professor of Physics for the Dijon Lycee in 1848, he was appointed professor of chemical sciences in the University of Strasbourg, where He met and courted Marie Laurent, daughter of the rector of the university in 1849. The couple was married the 29th of May 1849. Together, they had five children, but only two of them lived into adulthood. The other three were stricken by typhoid.


Pasteur became a professor at University of Strasbourg in 1848 He was appointed the chair of chemical chemistry in 1852. In 1854, Pasteur was made dean of the newly established faculty of sciences at the University of Lille, where he began his studies in fermentation. This was the time that Pasteur made his well-known quote:

“dans les champs de l’observation, le hasard ne favorise que les esprits prepares” (“In the field of observation, chance favors only the prepared mind”).

Then, in the year 1857, he relocated to Paris as director of studies in science in the Ecole Normale Superieure where he was in charge from 1858 until 1867. He also introduced a series of changes to raise the quality of scientific work. Examinations were more rigid, leading to better results, increased competition, and higher the prestige of the institution. A lot of his decisions were, however, rigid and authoritarian, which led to two major student protests. In the course of “the bean revolt” he declared that a stew of mutton that the students had rejected eating, would be served and consumed on Mondays. In another instance, he threatened to remove anyone who was caught smoking, and 73 out of the 80 students at the school quit.

The year 1863 was the time he was made professor of physics, geology, and chemical chemistry in the Ecole nationale superieure des Beaux-Arts in Paris. He held the position until the time of his resignation in 1867. He was appointed in 1867 to was appointed an chair for organic chemistry in Sorbonne however, he eventually quit the post because of his poor health. In 1867 the laboratory of the Ecole Normale for physiological chemistry set up upon the suggestion of Pasteur. the laboratory’s director was Pasteur from 1867 until 1888. In Paris Pasteur established his own institute, the Pasteur Institute in 1887, where he served as his director throughout the remainder of his life.


Throughout his life, Pasteur conducted research that brought about the new era of science and medicine. Through Pasteur’s discoveries, people can be living longer, and longer. His initial work with winemakers of France where the method he devised to kill germs and pasteurize them in the process of fermentation and meant that all kinds of liquids can now be legally sold, such as wine as well as milk and beer. He even received U.S. patent 135,245 for “Improvement in Brewing Beer and Ale Pasteurization.”

Other accomplishments include the discovery of a cure for specific virus that affected silkworms which was an enormous benefit to the textile industry. He also discovered cures for anthrax in chickens, cholera in chickens in sheep as well as rabies in human beings.

The Pasteur Institute

The Pasteur Institute
The Pasteur Institute

The year 1857 saw Pasteur was transferred to Paris in 1857, where he was offered several professorships. Personally, Pasteur lost three of his children to typhoid in the time, and in 1868, he was struck by an uncontrollable stroke that caused him to be partially paralyzed for the remainder all of his existence.

He founded his Pasteur Institute in 1888, with the intention of treating rabies as well as the study of contagious and virulent illnesses. The Institute was the first to study microbiology and offered the first ever class on the new field in 1889. In the year 1891 Pasteur opened another Institutes across Europe to further develop his theories. Today there exist 32 Pasteur institutes or hospitals across 29 countries around the world.

Louis Pasteur Experiment


In collaboration together with Balard, Louis became interested in the physical structure of crystals. He started working on two different acids. Paratartaric acid and Tartaric acid were chemically identical however they looked different when observed under microscopes. How can chemically identical substances appear different? Louis discovered that, when in solution both substances spin polarized light in different ways.

Louis then utilized his microscope and dissecting needle to meticulously dissect the crystals of both acids. He found that two kinds of crystals had mirror images of one another. The first proof of the chirality in chemical compounds. The thesis he wrote on this research was awarded an honorary doctorate in chemistry and physics in 1847. In 1848 the university offered him a job in the University of Strasbourg, where He was married to Marie Laurent. There were five kids, and three suffered from typhus. This was which later influenced Pasteur’s interest in infectious diseases.

Fermentation and pasteurization

In Strasbourg, Pasteur began studying fermentation. His research led to several innovations in the process of making beer and wine. The year 1854 was the time Louis took up a job at the University of Lille, where the university was approached from a nearby tradesperson investigate the cause of certain casks of fine vinegar made of beet juice were deteriorating. Pasteur looked at the good vinegar as well as the spoiled one under a microscope. He realized that the yeast responsible for causing the juice of beets to ferment was living organism. Casks that produce good vinegar had healthy yeast, whereas those that made the product that was rotten also contained rods of microscopic size that damaged the yeast.

Pasteur speculated that these tiny “microbes” were also living organisms that could be killed through boiling the vinegar. However, this could also alter the flavor in the vinegar. After careful testing in the lab, he found that bacteria that were infecting the vinegar could be killed through controlled heat of the vinegar to the temperature of 50-70 temperatures Celsius (122-140 temperatures (122-140 degrees F) before rapid cooling. The process is now referred to as pasteurization.

Spontaneous generation

In the 1860s, a lot of researchers believed that life on earth was a result of air by itself. Pasteur believed that air was the cause. The microbes attached by dust particles multiplied when they dropped from the air and into a medium that was suitable for reproduction. In 1859, the year in which Darwin’s “On the Origin of Species” was published, Louis Pasteur set out to prove that microbes can only be born from microbes.

In order to prove that dust particles in the air could be a source of contamination for microbial, Pasteur took vessels containing the sterile solution of nutritional broth to various locations. He then briefly opened the containers and expose them to air. He demonstrated that vessels exposed to low altitudes that had high levels of dust particles were infected with a lot more microbes than vessels exposed at higher altitudes , where the air was cleaner.

Even when critics insisted that it was air that caused the spontaneous generation Pasteur came up with a simple and elegant solution. He created specially “swan necked” glass vessels. The top of the vessels was bent into an S-shaped curvature which allowed air circulation, however it sucked in dust. In the vessel, the nutrients did not show any microbial growth, eliminating the spontaneous generation.

Louis Pasteur’s pasteurization experiment illustrates the fact that the spoilage of liquid was caused by particles in the air rather than the air itself. These experiments were important pieces of evidence supporting the germ theory of disease.
Louis Pasteur’s pasteurization experiment illustrates the fact that the spoilage of liquid was caused by particles in the air rather than the air itself. These experiments were important pieces of evidence supporting the germ theory of disease.

Silk worm crisis

Pasteur was chosen to head an investigation commission into an illness that affects silkworms. Through the microscope, Pasteur observed that adult moths and diseased worms displayed globules over their bodies. He determined that when mature moths sporting globules are permitted to breed, they would lay eggs with diseased eggs. He advised the silk farmers to keep a separate section of adults that had globules on them and let only healthy adults reproduce. The following spring, however, the “healthy” moths produced hundreds of eggs with disease. Pasteur received a lot criticism in the following two years, before he was able to pinpoint the reason.

Moths that had globules were suffering from a specific illness, but in reality there were two illnesses that killed silkworms. The globules are a type of microbe. However, Pasteur discovered a second illness which was previously undiagnosed. Pasteur also discovered that environmental conditions like temperature and humidity, as well as sanitation, affected the risk of contracting both types of diseases. This research helped to lay the foundations of the science of epidemiology.


In the early spring of 1879 Pasteur was certain that he was able to isolate the pathogen that causes chicken cholera. The tests showed that chickens inoculated with a solution that contained the suspected pathogen were all affected by the disease. Informing pupils to apply the vaccine to various birds at certain time intervals, Pasteur left his lab to spend a week in Paris.

When he left, the cholera pathogen was left to dry. Students were stunned to learn that the chickens exposed to the pathogen damaged didn’t get sick. After Pasteur returned, they decided to inoculate the chickens another batch of the cholera pathogen. After a few days, Pasteur noticed that chickens that were given this “useless” pathogen showed no indication of having been infected. Pasteur’s findings led him to discover that the virulence of pathogens can be altered artificially.

in 1882 Pasteur began to focus his energy on the issue of rabies. Rabies can be spread through contact with body fluids of an affected victim, such as saliva. A bite by an animal that is rabid is extremely risky and can be fatal. Pasteur looked into the tissues and saliva of animals that were rabid. Pasteur was not able to identify the microorganism that caused the illness. We now are aware that it originates from a virus that is too tiny to be detected by the microscopes that are available to Pasteur.

Pasteur was in need of an unreliable supply of infectious material to conduct his research. He obtained the material by letting a group of men stand over a dog who was aggressive. He then pushed the animal’s mouth wide for him to store the saliva in bottles. However, injecting saliva from affected animals could not result in rabies in animals tested. Through dissection and research, Pasteur discovered an indication that”the “causative agent” had to be concentrated in the brain and spinal cord of the victim in order to cause the disease.

Pasteur was convinced that vaccination using a less severe version of the disease, and then gradually more aggressive treatments would assist in strengthen the immune system. The issue of how to reduce the effect of the invisibly “causative agent” was solved by his assistant, who created a bottle that was specifically designed to dry the infected tissues. Pasteur discovered that the more the infectious material dried, the less likely it would cause rabies after injection.

In some time Pasteur created an immunization procedure that effectively protected dogs from contracting rabies. After a series of effective rabies injections for dogs over a period of 12 days the rabies extract was injected directly in their brains. To the satisfaction of Pasteur, all of the dogs was able to resist the rabies.

Pasteur was hesitant to test his cure on humans. Because he was unable to identify the microorganisms that caused this disease, Pasteur could only provide research evidence to prove that drying helped reduce the agent responsible for the disease. What if he injects the human body and led to a person contracting the disease rabies?

Louis Pasteur Quotes

“I am utterly convinced that science and peace will triumph over ignorance and war, that nations will eventually unite not to destroy but to edify, and that the future will belong to those who have done the most for the sake of suffering humanity.”

“The Greeks understood the mysterious power of the below things. They are the ones who gave us one of the most beautiful words in our language, the word ‘enthusiasm’ — ‘a god within.'”

“In the fields of observation chance favors the prepared mind.”

“Science knows no country, because knowledge belongs to humanity, and is the torch which illuminates the world.”

“There does not exist a category of science to which one can give the name applied sciences. There are sciences and the applications of science, bound together as the fruit of the tree which bears it.”

“The universe is asymmetric and I am persuaded that life, as it is known to us, is a direct result of the asymmetry of the universe or of its indirect consequences.”

“Posterity will one day laugh at the foolishness of modern materialistic philosophers.”


A few historians aren’t convinced by the general consensus regarding Pasteur’s findings. In the centennial year of Pasteur’s passing in the year 1995, an historian who specialized in the field of science Gerald L. Geison (1943-2001) released a book on Pasteur’s personal notebooks, which was only released just a decade before. Geison’s book “The Private Science of Louis Pasteur,” Geison claimed that Pasteur was a fraud who had fabricated stories about his major discoveries. Yet, others critics called Pasteur as fraudulent.


Louis Pasteur continued to work at the Pasteur Institute until June 1895 and then he took a break due to the severity of his illness. He died on the 28th of September 1895, following multiple strokes.


Pasteur was a complex man: the Inconsistencies and misrepresentations discovered by Geison in Pasteur’s journals indicate that he was not just an experimenter but a formidable speaker, combatant and writer who used deceitful information to influence opinion and to promote himself and his cause. However, his achievements were immense, including his studies on rabies and anthrax and the importance of hand washing and sterilization before surgery and, most important, bringing about the age of vaccines. His achievements remain a source of inspiration and help many millions.


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