Why did penicillin production become possible specifically in the early 1940s?
Mass production became possible in the early 1940s because roughly twenty-five years of USDA-funded mold fermentation research met British clinical results and wartime government coordination at the same moment. This is a historical paper, not a clinical study, so what follows is a documentary account rather than trial data.
Alexander Fleming, a Scottish bacteriologist at St. Mary’s Hospital in London, noticed in 1928 that bacteria seeded in staphylococcus cultures broke down on contact with a greenish mold, later identified as Penicillium notatum. Through the 1930s the practical value of penicillin remained in doubt, mainly because there was no feasible method to isolate and mass-produce it as a therapeutic compound for clinical use.
Howard Florey and his Oxford team took up that problem in 1936. On May 25, 1939, they ran their first successful penicillin test in mice, producing small quantities of stable penicillin-containing product from surface cultures and establishing its chemotherapeutic properties. In February 1941 they published successful clinical tests in patients. British pharmaceutical firms could not scale production under wartime constraints on materials and workforce, and the Oxford team also feared their samples falling into Nazi hands, so they turned to the United States, officially neutral until December 1941.
What the source documents:
- The American fermentation foundation predated the request: USDA scientists began studying fermentation in 1916, and in 1935 a group in Arlington, Virginia patented a “submerged” fermentation method in which mold grew throughout the medium. That method was used for mass-producing penicillin in 1941.
- Corn steep liquor changed the yield: In 1937 Andrew Moyer discovered corn steep liquor as a growth medium component, a method that led to a thirty-fold increase in penicillin production.
- The collaboration was physical and fast: In June 1941 Florey and Norman Heatley rubbed their lab coats with the mold and flew to the United States. Within a month they were working with American scientists in Peoria, Illinois, where a new fungal source from a moldy cantaloupe in a local market became a new medium.
- Government convening moved industry: Alfred N. Richards of the OSRD’s Committee on Medical Research organized the first penicillin meeting on October 8, 1941. Companies made no promises then, nor at the second meeting on November 17. At the third meeting on December 17, days after the United States entered the war, chief executives showed up willing to cooperate.
This historical paper by Harrison Shao, a senior-division entry in the National History Day 2024 competition published in The History Teacher, traces how the U.S. government’s role in building a research-industry network accelerated penicillin’s mass production in the early 1940s.
Dr. Kumar’s Take
I write antibiotic prescriptions without thinking about where the drug comes from. This paper is a useful corrective. The bottleneck was never the discovery. It was fermentation, recovery, purification, and packaging, the unglamorous engineering that turns a laboratory observation into something I can hand a patient.
The part I find most instructive is the timing of the December 17, 1941 meeting. The two earlier meetings produced no commitments from the companies. Shao is careful here, and I think correctly so: he says it is impossible to say whether the shift came from the research results, the government’s promise to absorb risk, the entry into the war, or some combination. That kind of restraint is rare in origin stories.
Historical Context
Fleming’s 1928 observation opened a new door for medical scientists to study antibiotic substances, and his own initial interest was in penicillin’s ability to break down cells rather than its antibiotic effect. What held the field back through the 1930s was not neglect of the finding but the absence of any workable method to isolate and mass-produce penicillin for clinical use.
The Oxford team’s mouse work in 1939 drew little attention in American media. The first New York Times coverage came on October 20, 1940, one of six science items in a single report, and the paper’s science writer Waldemar Kaempffert was doubtful, writing: “It looks as if penicillin contains something as powerful as sulfanilamide. What is it? Nobody knows as yet.”
What the Research Shows
A quarter century of fermentation research USDA scientists began studying fermentation in 1916. The first generation of chemists, led by Charles Thom, collected aspergilli and penicillium molds and examined their oxalic acid production capability, work that helped develop fermentation methods for mass-producing gluconic acid. In the 1920s the USDA began working with Pfizer & Co., which would become the world’s largest penicillin producer after 1941, on mold fermentation methods.
Two specific technical unlocks The 1935 submerged fermentation patent, growing mold throughout the medium rather than on its surface, was the method used for penicillin in 1941. Moyer’s 1937 corn steep liquor discovery produced a thirty-fold increase in penicillin production. Shao’s argument is that without these methods already mature, Florey and Heatley might have returned to Europe empty-handed.
The Anglo-American meetings Florey and Heatley first visited John Fulton, a physiology professor at Yale. Through him they met Charles Thom, the USDA’s principal mycologist, Robert Coghill, director of the USDA’s fermentation division, and Andrew Jackson Moyer, director of the Northern Regional Research Laboratory in Peoria. In Washington they met Ross G. Harrison of the National Research Council and Percy Wells of the Eastern Regional Research Laboratory. Peoria, with its group of fermentation specialists already developing large-scale mold fermentation, was the obvious place to work.
Government funding and allocation President Franklin D. Roosevelt established the War Production Board on January 7, 1942 to supervise production and allocation of defense supplies. The WPB supplied participating manufacturers with funds and materials for large-scale production. Anne Miller, the first American patient, was treated for septicemia on March 14, 1942 with a tablespoon of penicillin, half of Merck’s entire national store at the time, released by special WPB approval. She was cured.
The supply curve At the end of 1942 the United States had only enough penicillin to treat fewer than 100 patients. By August 1943 the reporting language had changed to “many millions of units.” By September 1943 the stock met the demands of the Allied armed forces, with the drug under strict WPB allocation and reserved for the military. On March 15, 1945 penicillin became available over the counter in U.S. pharmacies.
The clinical payoff In World War I, 12 to 15% of wounded soldiers treated in front-line hospitals died from infections. That fell to 3% in World War II. Early administration prevented severe sepsis from developing. After the war, penicillin was increasingly used against staphylococcal septicemia, syphilis, and gonorrhea.
Practical Takeaways
- The manufacturing method mattered as much as the molecule: Fermentation research funded from 1916 onward, not the 1928 discovery, is what made 1941 possible.
- Recognition lags contribution: Florey’s Oxford team went unrecognized until December 1943, when the American Pharmaceutical Manufacturers Association gave them an award. Fleming, Florey, and Ernst Chain won the Nobel Prize in 1945.
- The people who scaled it stayed anonymous: Shao’s central point is that the USDA scientists who supplied the fermentation methods are the least acknowledged figures in this history.
- Coordination, not just money, unlocked industry: The OSRD pushed for government-research-industry partnerships, and companies then formed collaborative teams to solve fermentation, recovery, purification, and packaging separately.
Related Studies and Research
- Penicillin: The Accidental Discovery That Changed Medicine and Won a War
- ACS Deep-Tank Fermentation: Pfizer’s D-Day Production
- Rethinking Antibiotic R&D: WWII Collaborative Model
- National WWII Museum: Penicillin’s Wartime Journey
FAQs
Why couldn’t penicillin be mass-produced in the 1930s?
There was no feasible method to isolate and mass-produce it as a therapeutic compound for clinical use. The Oxford team’s early stable products came from surface cultures in small quantities. The submerged fermentation method was patented in 1935 and was used for mass-producing penicillin in 1941.
What role did World War II play in enabling production?
The war cut both ways. It blocked British production, since British firms faced wartime constraints on materials and workforce, and it pushed the Oxford team to the United States. American industry then committed at the December 17, 1941 meeting, days after the U.S. entered the war, and the War Production Board supplied the funds, materials, and allocation authority from January 1942 onward.
How important was the collaboration between Britain and America?
Florey and Heatley brought the clinical results and the mold. American scientists at Peoria brought fermentation methods developed since 1916, plus the cantaloupe-derived fungal source that served as a new medium. Shao argues the American preparation was the essential foundation.
Who deserves credit that history has not given?
The USDA scientists. Shao’s thesis is that Charles Thom’s chemists, the Arlington group behind the 1935 submerged fermentation patent, and Andrew Moyer are the underappreciated figures, while the familiar story centers on Fleming’s accidental discovery and Oxford’s clinical tests.
Bottom Line
Penicillin reached mass production in the early 1940s because American fermentation research begun in 1916 was ready when British clinical proof arrived in 1941, and because the U.S. government built the research-industry network that turned that combination into supply. The 1935 submerged fermentation patent and Moyer’s thirty-fold yield improvement from corn steep liquor were the technical keys. The OSRD meetings and the War Production Board were the institutional ones. The result: from fewer than 100 patients’ worth of penicillin at the end of 1942 to enough for the Allied armed forces by September 1943, and over-the-counter availability by March 15, 1945.
