Scientists revive 5,300-year-old yeast from Oetzi the Iceman to bake sourdough

Scientists have isolated living yeast from the 5,300-year-old body of Oetzi the Iceman and used it to produce sourdough bread, according to a study published Wednesday in the journal Microbiome. The mummy was discovered in 1991 on the Similaun Glacier in the Ötztal Alps, 92 meters from the Austrian border.

He had been killed by an arrow wound to the back while crossing the mountains between present-day Austria and Italy.

Discovery of active microbes An Italy-based team at the Eurac Research institute in Bolzano examined samples taken from Oetzi's intestines, skin and the brownish water that formed when the body was partially thawed. They identified four yeast strains capable of surviving sub-zero temperatures.

Lead author Mohamed Sarhan told AFP that genetic damage patterns indicated the yeasts entered the body shortly after death. "These yeasts have accompanied Oetzi on his long journey through the millennia," study co-author Frank Maixner said in a statement.

The same analysis found a gut bacterium that is now rare in people from industrialized regions but persists among some populations in Africa and among 3,000-year-old remains from a salt mine in Hallstatt, Austria.

Bread-making experiment Researchers reproduced the yeast in laboratory refrigerators. After initial failures, three months of adjustments yielded a functional sourdough starter. "We had a very, very good sourdough," Sarhan told AFP. He added that brewing beer with the same yeast is under consideration.

The yeast also demonstrated the ability to metabolize phenol, a chemical applied to the mummy in 1991 to prevent fungal growth. Scientists noted this trait could have future applications in breaking down similar contaminants in the environment.

Expert caution and context Nikolay Oskolkov, a researcher at the Latvian Institute of Organic Synthesis who was not involved in the study, told AFP the samples were collected in 2010 and 2019. He said this timing provides limited evidence that the yeasts have persisted for millennia and suggested they may be more recent colonists of the remains.

Previous studies established that Oetzi was about 45 years old at death, carried a copper axe and arrows, and consumed a final meal containing deer, goat meat and wheat. In 2023, genetic analysis indicated his primary ancestry traced to early farming communities from the region of present-day Turkey.