In the Archaeological Museum of Alto Adige, in Bolzano, Ötzi rests in a cold cell at minus 6 degreeswith very high, almost saturated humidity. It seems the closest possible condition to the ice that has guarded him for millennia, after his death approximately 5,300 years ago and before its discovery, in 1991, in the Similaun area, between Italy and Austria. Yet that cold, so controlled, so museum-like, so apparently definitive, tells a less immobile story than we like to imagine. There is still movement on the Similaun mummy. Small, organic, stubborn. The Ötzi’s microbiome contains bacteria, fungi and yeasts capable of surviving, adapting and, in some cases, showing signals compatible with ongoing growth.
The study published on Microbiome brought together different techniques, from shotgun metagenomics to amplicon sequencing, from de novo metagenomic assembly to isolate genomics, to more precisely read the Iceman’s microbial landscape. The research group at Eurac Research in Bolzano, with Mohamed S. Sarhan, Marco Samadelli, Alberto Zink and Frank Maixner, worked on samples taken from the mummy, from the conservation environment, from the melt water and also from materials linked to the place of discovery. The result is a map much more complex than the usual display case idea: Ötzi appears as a dynamic biological systemcrossed by ancient traces, glacial presences and modern contaminations linked to conservation.
The cold leaves margin
The most delicate part of the research concerns precisely this: the cold room preserves, slows down, stabilizes, but leaves room for specialized life forms, accustomed to extreme conditions. The researchers distinguished three major microbial levels. The first belongs to the most remote past: microorganisms of the intestinal microbiota of Copper Age man, preserved in the internal tract of the mummy. The second comes from the Alpine glacier, therefore from the cold environment in which the body has remained for millennia. The third comes from afterwards, from the recovery of 1991 onwards: manipulations, museum environments, water spray to maintain humidity, inevitable practices when trying to conserve something which, by its nature, would slowly continue to change.
Inside the mummy the picture is more stable, with an ancient microbiome dominated by such microorganisms Clostridium and with DNA damage consistent with a long postmortem history. Among the identified taxa appear Romboutsia hominis, Clostridium moniliforme, Ruminococcus bromii, Treponema succinifaciens, Kineothrix sp. and Eubacterium sp. It’s a configuration that more closely resembles that seen in ancient human remains than contemporary Western microbiomes, shaped by industrial diet, antibiotics, modern hygiene and less exposure to natural environments. Ötzi, in this sense, also retains a small imprint of what our intestine was before modernity passed over it with ready meals, drugs and indoor lives.
Outside the body, however, the scene changes pace. The surface of the mummy and some internal waters host psychrophilic yeasts, i.e. those adapted to the cold, including Glaciozyma watsonii, Mrakia robertii, Phenoliferia glacialis and a kind of that Goffeauzyme. In particular Glaciozyme it has become dominant in more recent skin samples: in the comparison between 2010 and 2019, its relative abundance on the skin goes from 85% to 98%, with longer DNA fragments and reduced signs of damage. A technical detail, of course, but a decisive one: a DNA that appears less degraded, together with the increased presence of yeast, suggests a recent or ongoing proliferation, compatible with a slow life in humid and cold microenvironments.
The bread inside the display case
The discovery also has an unexpected, almost domestic impact. Some of these cold yeasts could be useful for low-temperature industrial processes, including food fermentation. In less laboratory words: they could also be used to make bread while consuming less energy, because active fermentation at room temperature or even in a refrigerator would reduce the need to heat the dough. The same yeasts could work during transportation, starting fermentation before arriving at the producer. The first experiments are still embryonic, with results to be improved and entrusted to groups specialized in the food sector, but the potential is there. Bread, maybe even beer. It seems like a bizarre deviation, but instead it fits perfectly into the story: an ice organism that becomes sober, silent, less energy-intensive technology.
However, the measure must be kept. Here charm risks outrunning prudence. The discovery of live or potentially active yeasts on the Similaun mummy opens up interesting possibilities, without turning Ötzi into a kind of archaeological sourdough starter ready for the baker’s counter. The research talks about strains to be better characterized, functions to study, applications to test. The transition from the laboratory to food production requires time, controls, skills and safety assessments. The most solid part, for now, remains knowledge: understanding how a microbiome lives in extreme conditions, how it changes under conservation, how it reacts to cold, humidity, oxygen and treatments used over time.
And here comes the less scenic part, perhaps the most important. Some microorganisms identified on Ötzi possess genes associated with the degradation of proteins, lipids, collagen and phenol. Collagen is a structural component of the skin and connective tissues of the mummy; proteases and lipases can help break down complex organic materials; the ability to degrade phenol is of interest because phenolic substances have been used in conservation practices in the past. The presence of these metabolic tools suggests an indirect risk to the integrity of the mummy, especially if some microbial communities transitioned from simple persistence to increased activity.
Preserve something that lives slowly
Ötzi’s body is being carefully monitored and his state of preservation is considered stable. The director of the Archaeological Museum of Alto Adige, Elisabeth Vallazza, recalled the importance of accurate microbiological control to avoid damage to the mummy, while Marco Samadelli underlined how the conservation conditions of glacial mummies still need to be fully understood. The phrase sounds technical, almost professionally prudent, yet it contains all the tension of the story: guarding such an ancient artefact means accepting that ice, skin, water, air and microbes are still negotiating with each other.
For this reason, the study insists on periodic genomic monitoring, rigorous control of oxygen and humidity, evaluation of nebulization practices and increasingly less invasive sampling strategies. Even the water used to keep the mummy moist can leave a microbial signature on surfaces, changing the external ecosystem over time. Conservation, therefore, becomes an ongoing relationship with what we are trying to protect. Every intervention can stabilize something and favor something else. Every parameter moved just a little can change a microscopic niche. The Similaun mummy still carries the man he was, the glacier that preserved him, the museum that protects him and the microorganisms that learned to live in the midst of all this. At minus 6 degrees, time slows down. It stops much less than we would like.
