Scientists Discover 5,000-Year-Old Yeast in Mummy, Successfully Make Bread

(Central News Agency, Paris, 3rd, Comprehensive Foreign News) Scientists have discovered yeast that may have existed for thousands of years inside the 'Iceman Oetzi'. They told AFP that they have successfully used the cultivated yeast to make sourdough bread.

'Iceman Oetzi' died after being shot in the back with an arrow over 5,300 years ago while walking in the Alps, which now form the border between Austria and Italy. At the time of his death, the Egyptian pyramids had not yet been built.

His body was subsequently covered by snow and ice and mummified, remaining in that state until 1991 when two German hikers discovered him in South Tyrol, northern Italy.

To preserve the mummy's condition, Iceman Oetzi has been kept at a constant low temperature of minus 6 degrees Celsius, the temperature at the time of his discovery.

This has allowed the scientific team to conduct careful research, providing an extremely rare window into the life of ancient humans.

According to the latest study published today in the journal 'Microbiome', a scientific team conducting research in Italy has discovered that ancient and modern microbes inside Iceman Oetzi remain active.

Lead author Mohamed Sarhan from Eurac Research in Bolzano, Italy, said: 'We did not expect to find yeast.'

The scientific team discovered four types of yeast capable of surviving below freezing in Oetzi's intestines, skin, and the 'slightly brown' water that came out when he thawed.

These yeasts only survive in extremely cold environments like Antarctica, so it is speculated that they entered the body at some point after Oetzi's death.

Sarhan said genetic analysis showed that the 'degree of DNA damage in Oetzi's intestines is very close to that of the original microbes,' suggesting these yeasts entered his body shortly after his death.

Co-lead author Frank Maixner said: 'These yeasts have accompanied Oetzi across thousands of years.'

The scientists then replicated and cultured these intestinal yeasts in a refrigerator.

Sarhan said: 'Every time we mention yeast, the first question everyone asks is: can we make bread with it?'

So they followed the public's interest and attempted to make sourdough bread.

The microbiologist admitted it wasn't smooth sailing at first, but after three months of effort, 'we made a very good sourdough bread.'

When asked if they had considered brewing beer with this yeast, he replied: 'It's on the list.'

The research report also mentions more serious potential applications for this yeast in the future.

When Iceman Oetzi was found in 1991, he was initially treated as a regular corpse, and a chemical called phenol was used to prevent fungal growth on the body.

However, this particular yeast can break down phenol, meaning it could potentially be used in the future to break down this chemical in polluted environments.

Sarhan said it is currently unclear whether this yeast has caused any damage to the Iceman Oetzi mummy itself, and he called for continued observation and research.

Nikolay Oskolkov, a researcher at the Latvian Institute of Organic Synthesis who was not involved in the study, warned that the yeast samples were only collected in 2010 and 2019, which 'provides quite limited evidence to prove that these yeasts have been multiplying inside the mummy for thousands of years.'

He personally believes it is more likely that these yeasts colonized the mummy more recently. (Editor: Chia-Min Tsai) 1150603

Study published in the journal Microbiome:
The Iceman's microbiome: unveiling millennia of microbial diversity and continuity