How humans domesticated the yeast that gives us wine and beer

Since the Neolithic Age, when the collection or capture of plant and animal species was no longer the basis of that species’ diet, our survival – and especially the development of civilization – has been the result of domestication.

Through agriculture and animal husbandry we have selected, improved and adapted 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 have also empirically tamed invisible creatures: the microorganisms needed to make fermented foods and drinks, especially lactobacilli and yeasts. Both are responsible for converting milk into cheese or yogurt, meat into sausage, and vegetables into pickles, wine, bread, and beer.

The historical impact of drunkenness

Yeast from bread, wine and beer, Saccharomyces cerevisiae, this article is right. It was probably domesticated in early agricultural settlements in Asia or the Near East. Archaeological remains, Mesopotamian tablets, and Egyptian papyri record recipes for brewing wine or primitive beer, which were very popular among these early civilizations.

Perhaps the oldest archaeological evidence for the consumption of fermented grains comes from the Natufian culture of the Mesolithic Age in the Near East, between 12,500 BC and 9,500 BC. C. We can speculate that the “magical” evolution of sugary grape juice into an intoxicating and long-lasting concoction occurred empirically in fruit or grain warehouses and was quickly mastered in terms of technology, certainly by Women in the family were in control even of women in the priestly caste.

Centuries before the Greek banquets witnessed in Plato’s writings, the consumption of fermented beverages was integrated into mystical rituals and seasonal festivals.

The Gospel itself, which is the foundation of Christianity, refers to these cults by combining bread and wine (products of fermentation). Saccharomycesas the axis of the Eucharistic rite.

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 consciousness that allowed them to connect with gods, mythical selves, nectar drinkers, soma, etc. . Despite its long history and historical importance—no historian can definitively deny that many of the decisions that changed the course of history were likely made after drinking alcohol—alcoholic fermentation had no scientific explanation until the 19th century . .

Until Pasteur’s arrival everything was just speculation

The first person to observe yeast in fermented foods was Antoni van Leeuwenhoek (1632-1723). But the hypotheses of physicist Charles Cagniard de la Tour (1777-1859) and naturalist Theodor Schwann (1810-1882) were proven, and these Hypotheses supporting the active role of these “animals” in the conversion of sugar into alcohol and carbon dioxide did not exist until Louis Pasteur (1822-1895) became interested in the biochemical transformations that occur in the production of wine and beer. Not scientifically proven.

Pasteur himself patented a method of beer production that he intended to use to surpass the quality of the 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 The Carlsberg factory separated grape juice, 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.This mixture came to be known as Saccharomyces carlsbergii Today it has been renamed Pasteurian yeast In memory of the father of microbiology.

Fermenting yeasts are the world’s most profitable microorganisms and are necessary for the baking, cocoa, wine and brewing industries and for the production of distilled beverages. It is estimated that in Europe alone we produce 1 million tonnes of yeast for commercial use every year.

We know everything about your genes

Saccharomyces cerevisiae Because of its ease of handling its vegetative and sexual reproductive cycles, it also served as a model for biology throughout the 20th century, ideal for easily testing Mendel’s laws. After all, what we know best at the genetic and molecular level are eukaryotes with true nuclei.

The 16 chromosomes contained in its genome were completely sequenced in 1996, an important overall test of subsequent human genome sequencing. Although hundreds of millions of years of divergent evolution separate humans from yeast, many physiological functions and cellular biochemical pathways remain perfectly preserved. So much so that geneticist Ira Herskowitz (1943-2003), one of the fathers of yeast cell biology, often responded to anyone questioning the validity of his model with the gem-like phrase “Yeast are single-celled humans.” sexual person 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 is the brains behind three Nobel Prize winners: Hartwell (2001), Schekman (2013) and Oshumi (2018). For his research on mechanistic models that control the cell division cycle (necessary in fighting cancer), vesicle trafficking between organelles, and the autophagy process.

To its importance as a biological model and industrial fermentation we must add its role as a probiotic, and its use in the chemical pharmaceutical industry for the production of very important drugs, such as hormones, on an industrial scale and at low cost ( human insulin) or a vaccine (Hepatitis B vaccine), or its use in the production of bioethanol in the clean energy sector.

antibacterial alcohol

Yeast has been on Earth for hundreds of millions of years. What did they do before we domesticated them?

We know they are spread on the legs and intestines of wasps, flies and other insects, including fruit flies, Drosophila melanogaster. They survive the winter as part of the gut microbiota of these insects. When the fruit ripens or any sugar-rich grape juice is found, greedy flies and wasps transport the yeast great distances (for them it is huge, the size of a red blood cell), which they give with their saliva and claws Fruit vaccination.

But there they meet formidable competitors with faster metabolisms: bacteria. Fortunately, nature is very clever, and when yeast consumes sugar, it converts it into a powerful antibacterial product: ethanol, a disinfectant and antiseptic that blocks bacteria and viruses.

Alcoholic fermentation is therefore a survival strategy that allows these small fungi to compete in their niche. By using them to brew beer or wine, humans were just opportunists who domesticated this alcoholic fermentation, which is so important in our gastronomic culture.

This article originally appeared on The Conversation. Read the original article.

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