A living ecosystem across the centuries, not a frozen capsule
Nos glaciares entre a Itália e a Áustria, um homem da Idade do Bronze jaz preservado há 5.300 anos — e agora, os microrganismos que habitavam seu corpo ressurgem para fermentar pão moderno. A descoberta de leveduras vivas nos intestinos de Ötzi levanta questões profundas sobre a persistência da vida, os limites do tempo biológico e o que significa herdar o mundo microbiano dos nossos ancestrais. Ciência e ceticismo caminham juntos: o que pertence verdadeiramente ao passado e o que já é contaminação do presente permanece em aberto.
- Quatro espécies de levedura foram encontradas nos intestinos de Ötzi, sobrevivendo congeladas por milênios em condições comparáveis às da Antártida.
- Após três meses de tentativas frustradas, pesquisadores conseguiram cultivar a levedura em laboratório e produzir um pão descrito como genuinamente excelente.
- A mesma levedura demonstrou capacidade de degradar fenol, substância usada na conservação da múmia, abrindo caminho para aplicações em remediação ambiental.
- O corpo de Ötzi também revelou uma bactéria intestinal quase extinta nas populações industrializadas modernas, sugerindo que a dieta rica em fibras da Idade do Bronze moldava um microbioma radicalmente diferente.
- Pesquisadores céticos alertam que as amostras foram coletadas décadas após a descoberta da múmia, levantando a dúvida central: a levedura é realmente antiga ou uma contaminação recente?
Em setembro de 1991, caminhantes encontraram num glaciar entre a Itália e a Áustria um corpo preservado com perfeição desconcertante. Ötzi, como foi batizado, morreu há 5.300 anos com uma flecha nas costas. O frio que o matou também o salvou — mantendo intactos seus tecidos, suas células e, surpreendentemente, os microrganismos que o habitavam.
Guardado a menos seis graus Celsius num museu em Bolzano, Ötzi revelou aos pesquisadores não apenas sua anatomia, mas um ecossistema microscópico vivo. Quatro espécies de levedura foram identificadas em seus intestinos, pele e na água que se formou quando a múmia parcialmente descongelou — organismos adaptados ao frio extremo, típicos de regiões como a Antártida.
Mohamed Sarhan, pesquisador responsável pelo estudo publicado na revista Microbiome, decidiu testar o impensável: usar essa levedura para fazer pão. Depois de três meses de experimentos fracassados, a equipe obteve sucesso, produzindo o que Sarhan descreve como um fermento natural genuinamente excelente. Os pesquisadores já cogitam usar a mesma levedura para produzir cerveja.
As possibilidades vão além da gastronomia. Como a múmia foi tratada com fenol para evitar crescimento fúngico, descobriu-se que a levedura antiga é capaz de degradar esse composto — o que abre perspectivas para sua aplicação na descontaminação de solos e águas poluídas. Um organismo de 5.300 anos pode ajudar a resolver problemas do século XXI.
O microbioma de Ötzi também surpreendeu em outro aspecto: uma bactéria intestinal quase desaparecida das populações industrializadas modernas foi encontrada em seus restos — e também em dejetos humanos de 3.000 anos preservados numa mina de sal austríaca. Tanto Ötzi quanto aqueles mineiros da Idade do Bronze consumiam muito mais fibras e grãos integrais do que os humanos contemporâneos.
Mas a dúvida persiste. O pesquisador Nikolay Oskolkov, que não participou do estudo, aponta que as amostras de levedura foram coletadas apenas em 2010 e 2019 — décadas após a descoberta da múmia, que desde então foi manuseada e exposta a ambientes modernos. A questão permanece sem resposta definitiva: o que nesse corpo realmente pertence ao passado, e o que já é nosso?
In September 1991, hikers crossing a glacier on the border between Italy and Austria stumbled upon a body so perfectly preserved it seemed almost recent. The man they found, later named Ötzi, had been dead for 5,300 years. An arrow lodged in his back told the story of his final moments during the Bronze Age. The natural freezing that claimed him became his salvation—his cells locked in ice, his tissues intact, his secrets still accessible to modern science.
Otzi now rests in a museum in Bolzano, Italy, kept at the same temperature at which he was found: minus six degrees Celsius. That cold has done more than preserve his body. It has kept alive the microscopic world that inhabited him. When researchers began examining his remains in detail, they expected to find bacteria, perhaps fungi. What surprised them was the discovery of yeast—four distinct species of it, thriving in his intestines, on his skin, and in the brownish water that pooled when the mummy partially thawed. These were organisms that could only survive in extreme cold, the kind found in Antarctica or high mountain ranges.
Mohamed Sarhan, the lead researcher on the study published in the journal Microbiome, found himself facing a question that seemed almost absurd once the yeast was identified: Why not try to bake bread with it? The genetic analysis suggested the yeast had arrived in Ötzi's body shortly after his death, its DNA damage patterns matching what you would expect from organisms that had been frozen for millennia. After three months of failed attempts in the laboratory, the team succeeded. They produced what Sarhan describes as genuinely excellent natural ferment. The researchers are now considering whether they might use the same yeast to brew beer.
But the practical applications extend beyond the kitchen. When Ötzi was first discovered, museum staff treated him with phenol, a chemical designed to prevent fungal growth. The ancient yeast proved capable of breaking down this compound. Scientists now believe it could eventually be deployed to clean contaminated environments, degrading phenol in polluted soil or water. A 5,300-year-old organism, preserved in ice, might help solve modern problems.
The body itself revealed other surprises. Analysis of Ötzi's microbiota uncovered a bacterium that has almost entirely vanished from modern human digestive systems in industrialized countries, though it persists in some African and South American populations. The same bacterium was found in 3,000-year-old human waste preserved in a salt mine in Austria. Both Ötzi and those Bronze Age miners consumed far more fiber and whole grains than contemporary humans do. The frozen man was not a static biological capsule, researchers concluded, but a living ecosystem—one that continued to function, however slowly, across the centuries.
Yet skepticism remains. Nikolay Oskolkov, a researcher who had previously identified fungi in Ötzi's remains but did not participate in this study, points out that the yeast samples were collected only in 2010 and 2019. That raises a crucial question: Did these organisms truly survive 5,300 years, or did they contaminate the body more recently? The evidence, Oskolkov suggests, is thin. The yeast may be far younger than the claims suggest, a recent arrival in a body that has been handled, studied, and exposed to modern environments for more than three decades. The question of what truly belongs to Ötzi and what belongs to us remains unresolved.
Citações Notáveis
When you say you have yeast, people immediately ask if you can use it to make bread—and that's exactly what we did— Mohamed Sarhan, lead researcher
The yeast accompanied Ötzi on his long journey through the millennia— Frank Maixner, study coauthor
A Conversa do Hearth Outra perspectiva sobre a história
So they actually baked bread with it? That seems almost too neat.
It does. But the real story isn't the bread—that's almost a side effect. The point is that yeast survived 5,300 years in a frozen body and remained viable enough to cultivate. That's extraordinary.
Why does it matter that it survived? We know things can be preserved in ice.
Because microorganisms are supposed to die. They need conditions to reproduce, to metabolize. Finding active yeast in a frozen corpse suggests the cold didn't just preserve the body—it preserved an entire ecosystem that kept functioning at some level.
But there's doubt about whether it's actually that old, right?
Yes. The samples were only collected in 2010 and 2019. That's decades after the body was discovered and handled repeatedly. It's possible the yeast contaminated the remains much more recently. The genetic evidence suggests it arrived soon after death, but we can't be certain.
So what's the real value here?
The yeast can degrade phenol, a chemical used to preserve the body. That's a genuine application. But more broadly, it's a window into what Bronze Age humans ate and how their bodies worked. The bacteria they found tells us about diet, about fiber intake. That's the archaeology.
And the bread?
The bread is what makes people listen.