Louis Pasteur - Contributions to Science

Louis Pasteur
Contributions to Science
Dr. Dhanya KC
Assistant Professor
Department of Microbiology
St. Mary’s College
Thrissur-680020
Kerala

Louis Pasteur, Dr. Dhanya KC, St.Mary’s College
https://www.biography.com/scientist/louis-pasteur
Louis Pasteur (1822 – 1895)
Pasteur is known as the father of
microbiology and immunology
A biologist, microbiologist and
chemist

Louis Pasteur was born on December 27, 1822, in Dole, France.
His father, Jean-Joseph Pasteur, was a tanner and a sergeant
major who received the Legion of Honor during the Napoleonic
Wars.
Pasteur earned his bachelor of arts degree (1840) and bachelor of
science degree (1842) at the Royal College of Besancon and
doctorate (1847) from the Ecole Normale in Paris.
In 1848, he became a professor of chemistry at the University of
Strasbourg.

In 1849 Pasteur observed that
Tartaric acid and racemic acid found in
sediment of fermenting wine have identical
chemical composition.
Upon intense inspection using a microscope,
Pasteur noticed that these identical molecules
have different spatial arrangement. One was
the mirror image of the other.
This discovery led to the branch of science –
‘stereochemistry’.
This experiment established that to study how
a chemical behave, along with its composition,
the structure and shape is also important.
https://chem.libretexts.org/Courses/Atha
basca_University/Chemistry_350%3A_Or
ganic_Chemistry_I/Chapter_5%3A_Stere
ochemistry_at_Tetrahedral_Centres/5.04
_Pasteur%27s_Discovery_of_Enantiomer
s

Until the second half of the 19th century, Many scientists and philosophers
believed in Spontaneous Generation - Life could arise spontaneously from
nonliving matter
Louis Pasteur disproved Spontaneous Generation - proved that all life comes
from preexisting life.
Disproved a theory held since Aristotle
https://courses.lumenlearning.com/microbiology/chapter/spontaneous-generation/
Pasteur demonstrated that in
sterilized and sealed flasks
no life forms develops and in
sterilized but open flasks
microbes could grow
Microorganism from air
contaminate sterile
solutions, but air itself does
not create microbes.

Pasteur’s next study in 1854 to 1862, as professor of
chemistry and dean at the University of Lille
To find solutions to the problems associated with alcoholic drink
manufacture
His studies showed that
living cells, yeast, are
responsible for forming alcohol
from sugar
contaminating microorganisms
make the fermentation sour
https://www.bonappetit.com/story/spontaneou
s-fermentation

Invents pasteurization
In 1863, at the request of the emperor of France, Napoleon III,
Pasteur studied wine contamination and showed it to be caused
by microbes.
• To prevent contamination, Pasteur heated wine to 50–60 °C
a process now known as pasteurization.
• It is used for the preservation of many foods and beverages,
particularly milk
http://www.dairymoos.com/what-is-pasteurization/

The silkworm larvae having pebrine are
covered in brown dots and are unable to spin
thread
Louis Pasteur identified the cause and
developed a method called ‘graining’ when a
plague of the disease spread across France.
Graining enabled elimination of
contaminated females and the preservation
of healthy eggs
This technique was adopted by silk
producers throughout the world.
http://biology.homeomagnet.com/silk
worm-diseases/
In 1865 Rescued the silk industry
Pebrine, or "pepper disease," a disease of silkworms, caused by
protozoa, mainly Nosema bombycis and other species.

• He concluded - this is due to a
microorganism that could
ferment only in the absence of
oxygen.
• Introduced the terms aerobic
and anaerobic to designate
organisms that live in the
presence or absence of oxygen
Pasteur effect
• Pasteur identified that the fermentation process could be
arrested by passing air (oxygen) through the fermenting
fluid - known today as the Pasteur effect.
https://basicmedicalkey.com/energy-conservation-in-metabolism-the-
mechanisms-of-atp-synthesis/

• In 1879, Pasteur worked with the
disease fowl cholera, or chicken
cholera which was rampant in
chicken coops at the time.
• When inoculated into a chicken,
the bacteria kill the bird -
Pasteurella multocida
• Pasteur used a weakened culture
of bacteria to inoculate chickens -
resulted in immune birds
• The principle of vaccination with
attenuated pathogens was
discovered.
https://sites.google.com/site/jl99323/bacterial/louis/pasteur
https://www.youtube.com/watch?v=HfEfpbQDiCw

• Anthrax is an infectious disease that affects cattle, sheep, etc
that can be transmitted to man.
• It was responsible for killing large populations of sheep in
France, detrimental to the economy.
• Pasteur developed a mild, harmless culture of anthrax bacteria.
Used this culture to vaccinate hundreds of livestock, and they
became immune to the disease.
In 1879 Pasteur worked with the disease
Anthrax caused by Bacillus anthracis.
http://www.pasteurbrewing.com/germ-theory-of-disease/

• In anthrax or chicken cholera vaccination the causative agents
are artificially weakened or attenuated to immunize the
animals
• This discovery revolutionized work in infectious diseases
• Pasteur gave these artificially weakened diseases the generic
name of "vaccines", in honour of Jenner's discovery

• In 1882, Pasteur worked with an epizootic of Swine
erysipelas
• He developed a vaccine against this bacterial infection
• He carefully studied and discovered several other
infectious diseases such as those caused by
staphylococcus, streptococcus and pneumococcus.

Pasteur then worked with rabies
• Rabies is a highly contagious,
infectious viral disease that
attacks the central nervous
system, transmitted via the bite
of rabid animals
• On 1885, Pasteur administered
his rabies vaccine on Joseph
Meister, a young man bitten by a
rabid dog and saved his life.
https://sites.google.com/site/jl99323/bacterial/louis/pasteur
To help treat future cases of rabies, the
Pasteur Institute was established in 1888
with monetary donations coming from all
over the world.

His medical discoveries provided direct support for the germ
theory of disease and its application in clinical medicine.
Although Pasteur was not the first to propose the germ theory, his
experiments indicated its correctness
He is regarded as one of the three main founders of bacteriology,
together with Ferdinand Cohn and Robert Koch
https://www.vision.org/world-problems-infectious-disease-pandemic-4352

Pasteur As a Physicist and a Chemist 1847 to 1862
• Crystallography
• Alcoholic Fermentation
Pasteur As a Biologist 1862 to 1877
• Spontaneous Generation
• Pasteurization: (Wine & Beer issues)
• Pasteur effect
• Silk Worm Diseases
Pasteur As a Microbiologist 1877 to 1887
• Fermentation & Pasteurization
• Germ theory of Disease and vaccination
• Silkworm Disease
• Anthrax
• Rabies
• Chicken Cholera
• Swine erysipelas

Louis Pasteur was the director of the Pasteur Institute, until
his death (due to stroke), and his body was interred in a
vault beneath the institute.
Pasteur's tomb is in a crypt that lies underneath the Pasteur Institute in Paris.
https://www.bbc.com/timelines/z9kj2hv

He is remembered as one of the founders of preventative medicine
Few people have saved more lives than Louis Pasteur
The vaccines he developed have protected millions
His insight that germs cause disease revolutionised healthcare
He found new ways to make our food safe to eat
Pasteur was the chemist who fundamentally
changed our understanding of biology

Chance favors the prepared mind.
Little science takes you away from God but more of it
takes you to Him.
Gentlemen, it is the microbes who will have the last word.
The role of the infinitely small in nature is infinitely
great.
It is not the germs we need worry about. It is our inner
terrain.
Louis Pasteur

There are no such things as applied sciences, only
applications of science.
When I approach a child, he inspires in me two
sentiments; tenderness for what he is, and respect for
what he may become.
Science knows no country, because knowledge belongs to
humanity, and is the torch which illuminates the world.
Science and Peace will triumph over Ignorance and War
Louis Pasteur

"One must work; one must work. I have done
what I could”
- Louis Pasteur's last words

"One must work; one must work. I have done what I could”
- Louis Pasteur's last words

Louis Pasteur - Contributions to Science

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