Whose discovery was penicillin?

The Scottish scientist Alexander Fleming discovered penicillin in 1928 when he noticed that a mould called Penicillium had contaminated one of his bacterial culture plates and killed the bacteria around it. Fleming identified the antibacterial substance but struggled to purify it in useful quantities. It was Howard Florey, Ernst Chain and their team at Oxford who, around a decade later, turned penicillin into a practical, mass-producible drug, just in time to save countless lives during the Second World War. The three shared the 1945 Nobel Prize in Physiology or Medicine. Penicillin launched the age of antibiotics and transformed the treatment of infection.