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Penicillium Notatum ― The Miracle Mould

penicillium notatum
Penicillum notatum samples: Preserved specimens of the mould used to make penicillin, Sir Howard W Florey, Alexander Fleming, Ernst Chain and team, Oxford, England, 1929–44.

Curator Tilly Boleyn uncovers the history of the world’s first antibiotic drug. This is an extract from the publication Icons, which can be purchased online

This fungus changed the world. It saved millions of lives and completely transformed our expectations of life and death. This type of multicellular fungus is also a mould. The sludge it exudes is lethal to many bacteria, and cures a huge range of infectious diseases. The world’s first widely available antibiotic, penicillin, was made from this sludge. It quickly defeated major bacterial diseases, and ushered in the antibiotic age.

These samples of Penicillium notatum, sometimes referred to as the ‘miracle mould’, link the Museum’s collection to one of the greatest scientific discoveries in medical history. They were grown in the laboratory of an Australian scientist, Sir Howard Florey, who drove this medical revolution.

Florey didn’t discover this organism or the substance it produces. He brought together a team who recognised its potential and proved it could be used to kill the deadly bacteria that cause infection, sickness and death. This discovery, made during World War II, when resources were scarce and human suffering enormous, changed the course of history.1

A number of scientific advances paved the way for Florey’s breakthrough. Almost a century earlier, the microbiologist Louis Pasteur, Florey’s childhood hero, had shown that microorganisms were responsible for diseases that had plagued humans throughout history. Surgeon Joseph Lister vastly improved surgery by pioneering the use of hand washing and sterile instruments. This meant doctors caused fewer fatal infections in their patients, but there was still no real medical treatment available if wounds became infected.

Before antibiotics people were terrified of infections. Common accidents like cutting yourself or scraping your knee could lead to infection and death. Pneumonia killed a third of those who developed it, women and babies often died during childbirth, and 80% of common bacterial infections ended in death.2 A diagnosis of scarlet fever, meningitis, tuberculosis, septicaemia or gangrene was often a death sentence.

Scottish scientist Sir Alexander Fleming’s discovery of penicillin in 1928 is one of the most famous accidents in medical history. He sneezed on an agar plate of staphylococcal bacterial growth. When he returned from holiday he noticed the plate had mould growing on it, some of which appeared to have killed bacteria in its path. Fleming isolated the mould, found it difficult to work with, wrote an article about it and moved on. That fickle fungus was Penicillium notatum. A decade later, through the monumental efforts of Howard Florey and his team, it would become the world’s first widely available antibiotic drug.

At the University of Oxford, colleagues spoke of Florey’s ‘genius for finding the heart of a problem’.3 But science is knowledge observed, tested and built on over time. While Florey certainly had a brilliant mind, he was able to build on the ideas, discoveries and research from scientists who came before him. An integral part of his genius, however, was his unconventional desire to collaborate. He brought people, expertise and information from a wide variety of scientific areas together in one research group.

These days, scientists from different fields work together all the time in research centres, but in the 1930s it wasn’t common at all. Florey’s lab at University of Oxford was an early example of real-time collaboration between usually separate areas of science — biology, bacteriology, biochemistry, pathology, physiology ― and medicine. Each scientist worked on their area of expertise but they often met to discuss their ideas and progress with the whole team.4

The team was small by today’s standards but uncommonly diverse for the time. Norman Heatley was a master of experimental improvisation, growing the mould with whatever was available — pots, bedpans and whatever else he could find. Sir Ernst Boris Chain and Edward Abraham worked on purifying the brown sludge that grew under the green fuzz. AD Gardner and Jena Orr-Weing looked at how penicillin worked with other bacteria; Margaret Jennings studied it in animals; and Ethel Florey worked on clinical trials.

This multidisciplinary collaboration made the extraction of penicillin possible, but even with these diverse minds working on the project, there were countless times when the project almost stopped short. Research funding was tight, as always, and World War II had started. At Oxford, Florey was known as the ‘bushranger of research’ because he would aggressively chase money for his projects.5 After exhausting all funding opportunities in the United Kingdom, Florey set his sights further afield. He successfully applied for funding from the Rockefeller Foundation in the United States, which enabled him to extract enough penicillin to conduct some limited animal and human drug trials.

After publishing the seemingly miraculous results of those experiments, Florey’s imagination, persistence and determination drove a medical revolution.6 His blunt, gruff, no-nonsense approach throughout his career contributed to the project’s ultimate success. The chairman of the US Medical Research Committee, Dr A Newton Richards, had worked alongside Florey early in his career. When the man Richards would later affectionately refer to as a ‘rough colonial genius’ crossed the Atlantic to seek funding, Richards ignored the scepticism of many experts and threw US government support behind Florey’s risky venture.7

This decision triggered the collaboration of scientists, governments, drug companies, industry, academics and medical practitioners on the ‘most extensive studies of a single biological substance in history’.8 Florey was instrumental in the creation of enormous networks and established data sharing across national and international borders at the highest levels.9

This collaboration and discovery probably wouldn’t have been possible in a time of peace. World War II was in full swing. The number of wounded, infected and dying soldiers was increasing rapidly. America’s reluctant entry into the war shortly after Florey’s meeting with Richards ensured its commitment to the massive and costly international cooperative effort to produce penicillin in large quantities. The combined efforts and action paid off. Enough penicillin was made for it to be used to treat allied troops on the D-day invasion at Normandy in 1944. Dr Royal de Rohan Barondes MD of the US Army Medical Corps treated injured soldiers with penicillin at Normandy. This wasn’t Dr Barondes’ first encounter with penicillin. He had been corresponding with Florey for a number of years and visited Florey’s lab at Oxford just before D-day. He received these samples of Penicillium notatum and a signed copy of Florey’s report on the treatment of war wounds as mementos of his trip. Their friendship continued through correspondence, packages and cards for many years. After Dr Barondes’ death, his grandson sold these items to the Museum — mementos of not only their friendship, but of one of the greatest advances in medical history.10

In 1945, the Nobel Prize in Physiology or Medicine was awarded jointly to Sir Alexander Fleming, Sir Ernst Boris Chain and Sir Howard Florey ‘for the discovery of penicillin and its curative effect in various infectious diseases’.11 Today, bacterial resistance to our current supply of antibiotics is on the rise. Finding a solution to a problem of this magnitude requires international collaboration of similar scale, and a scientific hero like Florey to stand on the shoulders of giants and save us all anew.



1 Lennard Bickel, Rise up to Life: A Biography of Howard Walter Florey Who Made Penicillin and Gave it to the World, Charles Scribner’s Sons, 1973.

2 Bob Beale, ‘Breaking the Mould’, in John Keeney (ed), Australia’s Nobel Laureates: Adventures in Innovation 1915–1996, ETN Communications, Roseville, 2004.

3 Bickel, 1973.

4 Dr Simon Torok, ‘Maker of the Miracle Mould’, ABC Science Online, 1998, www.abc.net.au. Accessed 6 July 2016.

5 Bickel, p 47.

6 Christopher Cheng and Linsay Knight, Australia’s Greatest Inventions & Innovations, Random House Australia Pty Ltd, Sydney, 2012, pp 18–21.

7 Bickel, p 153.

8 Bickel, p 182.

9 Bickel, p 183.

10 Correspondence, MAAS Archives 99/30/1:3.

11 The official website of the Nobel Prize. www.nobelprize.org. Accessed 5 July 2016.


Cover of Icons book publication.
Icons, published 2016.


Purchase Icons online or from MAAS Store and selected bookstores.