Scientists Discover Yeast in Ancient Iceman’s Guts, Bake Bread

More than 5,300 years ago – before the Egyptian pyramids were built – Oetzi was strolling through the Alps on the border of Austria and Italy when he was killed by an arrow in the back. He remained frozen in the ice until two German hikers stumbled across his mummified remains in 1991 in the northern Italian region of South Tyrol.

Scientists have discovered that yeast has been growing in Oetzi’s guts for thousands of years, telling AFP they used it to make a tasty sourdough bread. This stunningly well-preserved remains has been kept at minus six degrees Celsius – as his icy tomb – allowing scientists to carefully study Oetzi, who offers an incredibly rare window into ancient human life.

For the latest research published in the Microbiome journal on Wednesday, an Italy-based team found evidence that both ancient and modern microbial life remain active in the frozen body. Lead study author Mohamed Sarhan of the Eurac Research institute in Bolzano told AFP, “What we didn’t expect to find was yeast.”

Scientists discovered four different yeasts that can survive sub-zero temperatures in Oetzi’s guts, skin and water that melted off his body when he was partially unfrozen. Genetic analysis revealed DNA damage levels very comparable to the original microbes, suggesting the yeast entered his body soon after death.

The scientists then reproduced the gut yeast in a fridge. “If you tell anyone you have yeast, they immediately ask: can we use it for bread?” Sarhan said. After three months of effort, they had a very good sourdough.

When asked if the scientists were considering using the yeast to brew beer, he responded, “It’s on the list.” The study also contained more serious possible uses for the yeast, such as breaking down phenol in contaminated environments.

An analysis of Oetzi’s microbiome revealed a particular kind of gut bacteria that is almost non-existent among modern humans. It has been detected among tribes in Africa and South America and 3,000-year-old faeces preserved in a salt mine in Hallstatt, Austria.

The study said it “reveals that the Iceman is not a biologically ‘frozen’ time-capsule but rather a complex ecosystem.” Nikolay Oskolkov, a researcher at the Latvian Institute of Organic Synthesis, called for more research as he believes the yeast samples were relatively recent colonists of the mummy’s body.