The golden age of microbiology began with the work of Louis Pasteur and Robert Koch in the late 19th century. During this time, a number of disease-causing microbes were discovered, techniques for isolating and characterizing microbes were developed, and the role of immunity in preventing disease was understood. Specifically, Louis Pasteur disproved the theory of spontaneous generation, established the germ theory of disease, discovered the role of yeast in fermentation, invented the process of pasteurization, and developed vaccines for rabies, anthrax, and chicken cholera. Joseph Lister also pioneered antiseptic surgery through the use of carbolic acid.

1. GOLDEN AGE OF
MICROBIOLOGY
KESSIYA T PETER
B SC MICROBIOLOGY
GROUP 3

2. Main questions arose during golden age of
microbiology
 Is spontaneous generation of microbial life exist?
 What cause fermentation?
 What cause disease?
 How can we prevent infection and disease?

3. The development of microbiology
 Golden age of microbiology started with the work of Louis Pasteur and
Robert Koch .
.The major achievements in the golden age of microbiology :
 A number of disease causing microbes were discovered.
 Understanding microbial metabolism, techniques for isolation and
characterizing of microbes were developed .
 Scientist identified role of immunity in preventing disease and controlling
microbes .
 Development of vaccines for several diseases.
 Introduced techniques used to prevent infection during surgery.

4. LOUIS PASTEUR
THE FATHER OF MODERN
 1822-1895

5. LOUIS PASTEUR (1822-1895)
 Louis Pasteur was a French biologist , microbiologist and chemist.
 Born on Dec 27, 1822 ,France
 Known as the Father of modern microbiology,
 one of the founder of bacteriology
 known for :
 - experimental disproval of Spontaneous Generation Theory.
-Germ Theory of Diseases
-Role of yeast in fermentation
-Pasteurization
-Vaccines for Rabies ,
cholera vaccine
Anthrax vaccine

6. Experiment for the disproval of spontaneous theory of
generation– swan necked flask experiment
 The living organisms are arise from the non living matter– spontaneous theory
 After the discovery of microbes some proposed that the microbes is also arise by the
spontaneous generation that is from dust particles
 Louis Pasteur decided to approach against this theory . So he conducted an
experiment
 *Major materials are a swan necked flask and ordinary flask
 *He prepared a nutrient broth, placed two equal amounts of broth into both
flasks.
 *he boiled each flask to kill any living matter in the liquid . It is left to room
temperature and exposed to air .
 * He observed it after several weeks ,broth in the straight neck flask was discoloured
and cloudy, but the broth in the swan necked flask had no change.
 *The germ in the air is unable move to the broth and were trapped on the curved
neck. but the germs from the air move to the broth and contaminated it in the case
of straight necked flask.

7. Conclusion
 If the spontaneous theory is been a real phenomenon
Pasteur argued that broth in the curved neck flask would
eventually become reinfected .because the germs would
spontaneously generated .
 But the curved neck flask never become infected ,
indicating that the germs could only come from other
germs.

8. Germ theory of disease
. In 1861, Pasteur published Germ theory of
disease states that microorganisms known as
pathogens or germs can lead to disease. This
idea was taken by Robert Koch ,who began to
isolate the specific bacteria that cause
particular disease.

9. ROLE OF YEAST IN FERMENTATION
* showed that yeasts convert sugar into ethanol and co2
 Pasteur was the first to demonstrate
experimentally that fermented
beverages result from the action of
living yeast transferring glucose into
ethanol.
 Also concluded that it is a process that
occurs in the absence of air.
 * Louis Pasteur first described lactic acid
as a product of microbial fermentation.

10. pasteurization
 When working on the fermentation of wine, he noticed the spoilage of wine ,so he
introduced a technique;
 Pasteurization is the technique of heating liquids for the purpose of destroying virus and
other harmful microorganism present in it . But unable to kill spore forming bacteria.
 The first pasteurization test was completed by Pasteur and Claude Bernard on April
20,1862.
 Cause logarithmic reduction of viable organism.
 This method is applied to beer and milk.(heat beer 55c to prevent disease)
 Milk – holder method ,flash method.

11. Development of vaccines -1879
 Pasteur’s first important discovery of study of vaccination came in 1879 and
concerned a disease called chicken cholera.
 Chicken cholera , a contagious disease occur in poultry yards .(Pasteurella
multocida).
 He observed that older bacterial culture of chicken cholera bacillus lost its
pathogenicity due to the exposure towards air. but retained its ability to protect
birds against subsequent disease.
 This led to discovery of the term “attenuation”( reduce the virulence of a
pathogenic organism). When he perform his experiment with old cultures
chickens show mild symptoms and survived .that is antibody developed against
the chicken cholera immunity developed .

12. Anthrax -1879
.Anthrax caused by Bacterium Bacillus anthracis
. He applied previous method of immunizing chicken cholera to
anthrax.
. He attenuated the cultures of the Anthrax bacillus by
incubating them at a high temperatures 42-43
. He proved that the inoculation of such cultures in animals
induced specific protection against anthrax.
. It was Pasteur first coined the term “Vaccine”.

13. Rabies -1882
 Rabies is a viral disease that cause the inflammation of the brain in humans and other
mammals( zoonotic : animals to humans).
 Commonly cause by the dog bite or bat bite through its saliva.
 Pasteur suspect the agent cause the rabies was a microbe that is too small to visible
under Pasteur’s microscope.
 Pasteur inoculated rabid rabbit which died before 15 days and isolate the virus from the
spinal cord of the rabbit
 He injected the attenuated virus on 9 year boy Joseph Meister, and he was saved after
several weeks.

14. Joseph lister
The father of anti septic surgery
1827- 1912

15. Joseph lister (1827-1912)
. A British surgeon and a medical
scientist
. born in England.
 Know for pioneer of antiseptic
surgery

16. Discoveries
. He tried to stop bacteria from getting into a human body.
. Lister sprayed carbolic acid or phenol, which was used to
remove the smell from sewage.
. He sprayed it on surgical instruments ,wounds and dressings ,
and found a big reduction of infections
. Wounds no longer became septic ,so the carbolic acid was an
antiseptic.
. He made surgeons to wear gloves and wash their hands before
and after operations with carbolic acid diluted with water.

17. overview
Golden age of microbiology
Louis Pasteur
 Father of modern microbiology
 disproved spontaneous theory
 germ theory of disease
 role of yeast in fermentation
 Pasteurization
 vaccine against chicken cholera ,anthrax ,rabies.
 Joseph Lister
. Father of antiseptic surgery.
. used carbolic acid for antisepsis procedures.

18. Thank you
 By group 3