- 1928, Alexander Flemming, left a bacteria culture by an open window.
- He noticed mould growing, but around it there was dead bacteria.
- He found this mould was penicillium notatum from which he extracted penicillin.
- Flemming gave up on culturing it because he couldn't extract very much.
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Howard Florey and Ernst Chain
- In WW2, Howard Florey and Ernst Chain extracted enough penicillin to use it. But they ran out.
- Luckily they found a similar mould on a melon, which held up to 200x more penicillin.
- By 1945 enough was being produced to treat 7 million people a year.
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Modern Penicillin Production
- Mould grown in a sterilised medium containing sugar, amino acids, mineral salts, and other nutrients.
- Penicillin only grows once nutrients are used up.
- So there's a 40-hour lag phase betweeb start of fermentation and penicillin production.
- Then there's a 140 hour period of extraction.
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