Alexander Flemming: a doctor and bacteriologist who discovered penicillin, receiving the Nobel Prize in 1945. Born in 6/8/1881, Ayrshire, Scotland. His father was a farmer. He served as a physician in WW1 and studied medicine. He attended 3 schools before moving to London in 1895, where he lived with his older brother, Thomas Fleming. In London, Fleming finished his basic education at the Regent Street Polytechnic.
He planned to become a surgeon, but he changed toward the then-new field of bacteriology after a temporary position in the Inoculation Department at St. Mary's Hospital . He developed his research skills with the guidance of bacteriologist and immunologist Sir Almroth Edward Wright, whose revolutionary ideas of vaccine therapy represented an entirely new direction in medical treatment.
Discovering penicillin: Fleming returned to his laboratory in September 1928 and noticed that whilst he spent a month away with his family a culture of Staphylococcus aureus he had left out had become contaminated with a mold (later known as Penicillium notatum). He also discovered that this mold had destroyed the surrounding colonies of staphylococci.
He thought that he found an enzyme more powerful than lysozyme, On further investigation he found out that it was not an enzyme at all, but an antibiotic -- one of the first to be discovered. He didn't develop the substance further alone as he had done previously but instead recruited two young researchers. They failed to stabilize and purify penicillin, but Fleming pointed out that penicillin had clinical potential, both in topical and injectable forms, if it could be developed properly.
Howard Florey and his co-worker, Ernst Chain led a team of scientists from the University of Oxford and they managed to isolate and purify penicillin so that it could be produced as a drug. At first supplies of penicillin were very limited, but by the 1940s it was being mass-produced by the American drugs industry.
During WW2 the antibiotic penicillin came into good use. It helped save the lives of wounded soldiers and was able to help reduce the spread of infection in general.