The Tiny Organism
that Changed the World
From brewing beer in ancient Rome to making biofuels in high-tech labs, yeast has been shaping human life for thousands of years. Explore its journey through history and see how this tiny fungus is still driving innovation today!
Yeast Originates in China
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Recent genomic studies show Saccharomyces cerevisiae (the yeast used in bread and beer today) originated in China, spreading westward via the early Silk Road. They brewed a mead-like drink made from rice, honey, and fruit.
Beer & Wine Brewing in Sumer, Babylonia & Georgia
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Fermentation practices using yeast were observed in ancient Sumer and Babylonia for beer and wine, as well as early winemaking in present-day Georgia.
Bread Baking in Ancient Egypt
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Egyptians developed leavened bread using wild yeast, coinciding with beer brewing.
Bread Baking in Ancient China
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Archaeological findings reveal sourdough bread production using yeast in China, specifically in the Subeixi cemetery.
Roman Bakers
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Pliny the Elder records that professional bakers using yeast-based techniques emerged in Rome around this time.
Discovery of Yeast Under Microscope
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Anton van Leeuwenhoek describes yeast's microscopic appearance, marking the first visual identification. This type of microscope was invented and used by Leeuwenhoek (1632-1723).
Term “Yeast” Defined
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J.H. van den Broek defines yeast as vegetative cells in fermentation, separating it from other forms. The word “yeast” as we know it today was not associated with fermentation until 1859, when J.H. van den Broek, working in Utrecht, Netherlands, identified vegetative cells that existed and replicated in fermenting forms, which he dubbed "Gist" which sounds like yeast.
Fresh Commercial Yeast for Baking was Developed
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Compressed yeast production begins in England, Germany, and the Netherlands, streamlining commercial bread baking.
Pasteur’s Fermentation Discovery
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Louis Pasteur confirms yeast as a living organism essential to fermentation, revolutionizing microbiology. When Pasteur described/discovered the fermentation process, he established the key role of yeast as the microorganism responsible for alcoholic fermentation. He unveiled these mysteries by proving that the yeast cell can live with or without oxygen.
First Sterile Yeast Production Patent
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Alfred Jörgensen & Axel Bergh filed the first yeast production patent emphasizing sterility and modernizing yeast manufacturing. The first known patent that followed Pasteur’s insistence on the sterility of both media and equipment was in 1891, by Jörgensen and Bergh in Sweden. Sterility helps to ensure that no other microbes (yeast or bacteria) are present that could contaminate the fermentation.
First Eukaryote Genome Sequenced
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Yeast becomes the first eukaryote with its genome fully sequenced, showing genetic similarities to humans. By May 1996, the first complete genome sequence of a eukaryote, the yeast Saccharomyces cerevisiae, was obtained. At that time, it was the largest genome sequenced to date. It contains just over 12 million base pairs packaged in 16 chromosomes. Yeast has approximately 6,000 genes in all and roughly a third of these genes are related to human genes.
Recent: Revival of Ancient Yeasts
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Yeast can survive for thousands of years and contributes to the understanding of ancient food and beverage habits. Researchers have revived yeast from 5000-year-old clay vessels, extracting it from microscopic pores in ancient pottery. Team up archaeologists, microbiologists, and a craft brewer, and they got a modern spicy and fruity ale beer. Ancient culinary practices in modern day. Cheers!
Gases, acids and alcohol. This is fermentation.
Fermentation is nature’s way of transforming one thing into another. It’s a biological process where yeast and other microbes break down sugars and convert them into gases, acids and/or alcohol. This is what makes bread dough rise, turns grape juice into wine and preserves foods like kimchi and cheese. But fermentation isn’t just about food — it’s a chemical superpower that life on Earth has been using for billions of years.
The dough
In dough, yeast consumes carbohydrates (sugars), releasing CO₂ bubbles that get trapped and make bread fluffy.
It is a simple chemistry that transforms humanity
C6H12O6 (glucose) + 2 ADP + 2 Pi → 2 C2H5OH (ethanol) + 2 CO2 + 2 ATP
A simple reaction that is the basis for alcoholic beverages, bread dough, savory food, ethanol fuel, plant-based plastics, and much more.
During fermentation yeast produces bubbles of gas (CO2) – especially in bread dough or brewing liquids – making things rise or froth. It also produces alcohol (ethanol) which has been a part of many cultures since the dawn of civilization.
Yeasts and bacteria in sourdough are BFFs. Yeasts like Candida milleri team up with LAB to create alcohol and acids that lock out mold. It’s a party in your loaf that keeps it fresh longer – no chemicals needed!
The first step is to thaw the sample and plate them to see if the yeast has survived and can still grow and reproduce. In petri dishes, tubes and then flasks, a tiny amount of engineered yeast is grown and expanded under ideal conditions of temperature, pH, oxygen, nutrients.
A few starter cells multiply into billions, enough to see if they can work as efficient cell factories for our product. These healthy, productive yeast cells are the foundation for everything that comes next in the lab or factory.
From a few dormant cells to billions
Fermentation — Turning Sugar into Solutions
Industrial fermenters can hold thousands of liters – enough to fill a small swimming pool with yeast culture bubbling away.
Harvesting — Getting Out the Good Stuff
Some byproducts, what before was considered waste, are now used as food for new cell factories or as raw material to create new products. This is an example of creating a circular economy, where nothing goes to waste and all can be reused for something else. True circularity though, has not been achieved, as a lot of CO2 is produced which remains unused. Maybe you can be the first to find a way?
This clear liquid may contain nutrients, (spent media and products produced by yeast which are of no interest (byproducts) as well as the product you want to manufacture. The next step is to isolate the product from all the other things in the supernatant.
This is called purification. It is usually a multi-step process requiring different types of machines and procedures, such as microfiltration, ultrafiltration, and chromatography, where you separate things according to their weight, size, and chemical composition.
We made it: 1 mg of pure product!
The final analysis
Once purified, the product is cleaned for any impurities it might have through filtration and changing solutions (buffer exchange). It is then analyzed for purity. The level of purity depends on its final use, for example: pharma requires high purity, food no toxicity, and household products require that the functionality is not affected by the impurities. You also must make different chemical analyses to determine that the product complies with the requirements needed (activity, solubility, toxicity, reactivity, stability, etc.). Once cleared, it is prepared for shipment to be tested in the real world!
A tiny ally for a sustainable future
Yeast isn’t just for baking bread or brewing beer — it’s a powerful tool for building a better world. In the way that yeast can produce ethanol/alcohol, scientists are now able to engineer yeast to produce other things such as medicines and sustainable materials. Engineered yeast can also help clean up pollution and help us solve big problems in smart, natural ways.
With science and curiosity, we can keep unlocking its potential to live more sustainably every day.
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