Penicillin production began in Britain on a small scale in 1941 due to World War II. Dr. Florey visited the US and Canada with a sample mold in July 1941. He was recommended by an American professor to meet the head of the USDA research laboratory in Peoria, Illinois, Dr. Robert Coghill. Dr. Coghill suggested deep fermentation could make the production of penicillin more efficient and convenient.
Image Courtesy: blog.europeana.eu