Contributions of louis Pasteur

This slides describes about the contributions of louis Pasteur and his work towards Microbiology
Louis Pasteur is the Father of modern Microbiology

1. CONTRIBUTION OF LOUIS PASTEUR NAME : NISHA R REG NUM : BP211511 COURSE : Msc . APPLIED MICROBIOLOGY TITLE : CONTRIBUTION OF LOUIS PASTEUR DATE : 15/11/2021 SUBMITTED TO : Dr.SARANYA

2. CONTRIBUTION OF LOUIS PASTEUR Louis Pasteur was the French Chemist, Biologist & Microbiologist and “Father of Modern Microbiology”. Louis Pasteur is a Chemistry Professor from France who disproved the Spontaneous Generation Theory completely by his “Swan Neck Flask ”Experiment.

3. Main contributions of Louis Pasteur includes ✓ Disproved the Spontaneous Generation Theory. ✓ First coined the term “Microbiology” for the study of organisms of microscopic size. ✓ Louis Pasteur proposed the “Germ Theory of Disease”. He stated that disease cannot be caused by bad air or vapor but it is produced by the microorganisms present in air. ✓ Liquid media concept – Louis Pasteur was the first who used Nutrient broth to grow microorganisms. ✓ Demonstrated the term Virulence (ability of microbe to cause disease) of bacteria. ✓ Introduced the term “Attenuation” that means reduction of Virulence of pathogens by prolonged cultivation.

4. ✓ Discovered the Yeast fermentation in fruits (Conversion of sugar to ethanol and CO2) fruit, Butyric acid fermentation and Lactic acid fermentation (sugars could be converted to Lactic acid by bacteria). ✓ Sorted different microbes giving different taste of wine. ✓ Louis Pasteur selected a particular strain (Yeast – Saccharomyces cerevisiae) for high quality wine. ✓ Louis Pasteur introduced the sterilization techniques and developed Steam sterilizer, Hot air oven and Autoclave (developed by Charles Chamberland who was the student of Louis Pasteur). ✓ Louis Pasteur described the method of Pasteurization of Milk and Wine.

5. ✓ Louis Pasteur discovered that the protozoa Nosema bombycis is responsible for causing Pebrine disease in silk worm. He suggested that disease free caterpillars can eliminate the disease. ✓ The term “Vaccine” was first coined by Louis Pasteur. ✓ Louis Pasteur developed Rabies vaccine (a killed or inactivated microbe to induce the immunity) against Rabbis from the brains and spinal cord of rabbit. On July 6, 1885, Louis Pasteur vaccinated Joseph Meister, a nine-year-old boy who had been bitten by a rabid dog. ✓ Louis Pasteur also developed the Chicken cholera vaccine (Attenuated Vaccine) (Pasteurella multocida ) & Anthrax vaccine (Bacillus anthracis) (Attenuated Vaccine).

6. ✓ Pasteur Effect – Louis Pasteur unexpectedly discovered that the Fermentation process could be arrested by passing air (oxygen) through the fermenting fluid, a process known today as the “Pasteur effect”. He concluded that this was due to the presence of a life-form that could function only in the absence of oxygen. This led to his introduction of the terms “Aerobic” and “Anaerobic: to designate organisms that live in the presence or absence of oxygen, respectively. ✓ Louis Pasteur further proposed that the phenomena occurring during “Putrefaction” (decomposition of organic matters) were due to specific germs that function under Anaerobic conditions.

7. ✓ Molecular asymmetry - In studying crystals of Sodium ammonium tartrate, Louis Pasteur found that although they had the same chemical composition, they did not necessarily have the same structure. He noted that the molecules occurred in two mirror-image arrangements that could not be superimposed. This Molecular asymmetry, or Chirality (mirror image), is the foundation of a branch of science known as Stereochemistry.

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