Short answers, pulled from the story.
Scottish physician Alexander Fleming discovered penicillin on the 3rd of September 1928 while working at St Mary's Hospital in London. He published his findings in the British Journal of Experimental Pathology on the 10th of May 1929.
Ernst Boris Chain and Howard Florey began their project at Sir William Dunn School of Pathology at University of Oxford in 1939. They secured funding from the Medical Research Council in September 1939 and received support from the Rockefeller Foundation later that year.
The Oxford team collaborated with American pharmaceutical companies including Pfizer, Merck, Squibb, and Lederle to develop fermentation techniques. Researchers used corn steep liquor to increase yield tenfold and employed reverse extraction processes to purify the drug for clinical use.
Dorothy Hodgkin determined the correct chemical structure of penicillin using X-ray crystallography at Oxford in 1945. The compound contains a beta-lactam ring which serves as the core nucleus for all penicillins and related antibiotics.
Researchers developed second-generation semisynthetic beta-lactam antibiotic methicillin in the United Kingdom in 1959 to counter resistant bacteria. This innovation allowed scientists to attach side chains to the 6-aminopenicillanic acid nucleus to create drugs effective against strains like MRSA.