Since the Neolithic period, when the gathering or capture of plant and animal species was no longer the basis of that species’ diet, our existence—and especially the development of civilizations—has been a result of domestication.
Through agriculture and animal husbandry we select, improve and adapt to our needs: cereals, fruit trees, garden plants, birds and ruminants for the production of eggs, meat, milk… and more recently, even fish.
But sometimes we forget that we also empirically domesticate invisible organisms: the microbes needed to make fermented foods and beverages, especially lactic acid bacteria and yeast. Both are responsible for converting milk into cheese or yogurt, meat into sausage, and vegetables into sauerkraut, wine, bread, and beer.
The historical impact of drunkenness
Yeast from bread, wine and beer, Saccharomyces cerevisiae, which is what this article is about. It was probably domesticated in the earliest agricultural settlements in Asia or the Near East. Archaeological remains, Mesopotamian tablets, and Egyptian papyrus document recipes for making wine or the original beer that was popular in these early civilizations.
Perhaps the oldest archaeological evidence for eating fermented grains comes from the Mesolithic Natufian culture of the Near East, from 12,500 BC to 9,500 BC. C. We can surmise that the “magical” evolution of sugary grape juice into an intoxicating and immortal concoction took place in the fruit or cereal store and soon became dominant in technology, certainly by the women of the family and clan Dominant, even in the priestly caste.
Many centuries before the Greek feasts witnessed by Plato’s writings, the consumption of fermented beverages was incorporated into mystical rituals and seasonal festivals.
The Gospel itself is the basis of Christianity, referring to these cults that combined bread and wine, the product of the fermentation of bread and wine. Saccharomycesas the axis of the Eucharist ceremony.
In the context of these rituals, the state of intoxication induced by fermented beverages can be interpreted in the first civilizations as a state of supernatural awareness that enabled them to connect with the gods, who themselves were, according to mythology, the gods of nectar, soma, etc. drinker. Despite its antiquity and historical weight—no historian can outright deny that many decisions that changed the course of history were likely made while drinking—alcoholic fermentation was not scientifically explained until the 19th century. .
Before Pasteur arrived, it was all just speculation.
The first person to observe yeast in fermented foods was Antoni van Leeuwenhoek (1632-1723). But the hypothesis of the physicist Charles Cagniard de la Tour (1777-1859) and the naturalist Theodor Schwann (1810-1882) was proved, these Hypotheses supporting an active role for these “animals” in the conversion of sugar into alcohol and carbon dioxide were not made until Louis Pasteur (1822-1895) became interested in the biochemical transformations that occur in wine and beer production Be scientifically proven.
Pasteur himself patented a method of beer production with which he intended to surpass the quality of broth produced by Germany’s enemies during the Franco-Prussian War. The application of pure culture techniques developed by Pasteur himself and his German rival Robert Koch (1843-1910), inspired Emil Christian Hansen (1842-1909) from Copenhagen From grape juice at the Carlsberg factory, where he worked as a microbiologist, to brewer’s yeast.This yeast is a hybrid yeast Saccharomyces cerevisiae Yeast domesticated and adapted to cold climates, Bayan yeast.The mixture was subsequently named Karlsberg yeast
today it has been renamed Pasteur yeast In honor of the father of microbiology.Fermenting yeast is the most profitable microorganism in the world and is needed in the baking, cocoa, wine and brewing industries, as well as in the production of distilled beverages. It is estimated that in Europe alone we produce 1 million tons of yeast per year for commercial use.
We know everything about your genes
Saccharomyces cerevisiae It was also a model for biology throughout the 20th century, thanks to its tractable cycle of nutrition and sexual reproduction, best suited for easy testing of Mendel’s laws. After all, the things we know best at the genetic and molecular level are eukaryotes with true nuclei.
The complete sequencing of the 16 chromosomes comprising its genome was performed in 1996, an important overarching test for the subsequent sequencing of the human genome. Although hundreds of millions of years of divergent evolution separated humans from yeast, many physiological functions and cellular biochemical pathways are still well preserved. So much so that geneticist Ira Herskowitz (1943-2003), one of the fathers of yeast cell biology, often used the gemstone phrase “Yeast is a single-celled human being” to answer any doubts about the validity of his model Sexual people, and solved the problem. Ironic, but determined to have any possible discussion about it.
And in the 21st century, using Saccharomyces cerevisiae As a model, he has won three Nobel Prizes: the Hartwell Prize (2001), the Schekman Prize (2013) and the Oshumi Prize (2018). For his work on mechanistic models controlling the cell division cycle (essential for fighting cancer), vesicle trafficking between organelles, and autophagy.
In addition to its importance as a model organism and industrial fermentation, we must add its role as a probiotic, and its use in the chemical pharmaceutical industry to produce very important drugs such as hormones on an industrial scale and at low cost ( human insulin) or vaccines (hepatitis B vaccine), or their use in the production of bioalcohol in the clean energy sector.
antibacterial alcohol
Yeast has existed on Earth for hundreds of millions of years. What were they doing before we domesticated them?
We know they travel on the legs and guts of wasps, flies and other insects, including fruit flies, Drosophila melanogaster. They survive winter as part of the gut microbiota of these insects. When the fruit is ripe or finds any sugar-laden juice, voracious flies and wasps transport the yeast great distances (well, huge for them, they’re the size of red blood cells) and they stretch it with their saliva and legs Inoculate into fruit.
But there they encounter formidable competitors with faster metabolisms: bacteria. Fortunately, nature is very smart, and yeast, as it consumes sugar, converts the sugar into a powerful antimicrobial product: ethanol, a disinfectant and antiseptic that stops bacteria and viruses.
Alcoholic fermentation is therefore a survival strategy that allows these small fungi to compete in their niche. By using them to make beer or wine, humans are just an opportunist who has domesticated this alcoholic fermentation, which is so important in our food culture.