2026年6月3日 / 美国东部时间上午9:41 / 哥伦比亚广播公司/法新社
科学家们发现，一具名为“冰人奥茨”的冰冻木乃伊的肠道中已经存在了数千年的酵母，并告诉法新社，他们用这种酵母制作了酸面包。
五千三百多年前——也就是埃及金字塔建成之前——奥茨当时正在奥地利和意大利边境的阿尔卑斯山漫步，被一支箭射中背部身亡。
他一直冰冻在冰层中，直到1991年两名德国徒步旅行者在意大利北部南蒂罗尔地区发现了他的木乃伊遗骸。
从那时起，他保存完好的遗骸一直被保存在与他的冰墓相同的温度下：零下6摄氏度。
这让科学家们得以仔细研究奥茨，他为我们了解古代人类生活提供了极其罕见的窗口。
在周三发表于《微生物组》杂志的最新研究中，一个意大利团队发现有证据表明，古老和现代的微生物都在这个冰冻的身体中保持活跃。
“我们没料到会发现酵母，”该研究的主要作者、意大利博尔扎诺欧洲研究学院的穆罕默德·萨汉告诉法新社。
1991年，被称为“奥茨”的5300岁木乃伊在抵达博尔扎诺考古博物馆后不久被拍摄到。西蒙娜·克雷帕尔迪/美联社/达普德通讯社
“他的体内存在着有生命、具有代谢能力的生物体，它们正在积极响应周围环境，”萨汉告诉路透社。“这些适应寒冷的酵母正在生长。某些细菌已经在他的组织中定植并存活了数十年。从非常真实的意义上说，这具木乃伊是一个活的生物界面——连接古代世界和现代的交汇点，5000年前的微生物与近十年才出现的有机体在此共存。”
“非常棒的酸面包”
科学家们在奥茨的肠道、皮肤以及他部分解冻时从身体融化出的“褐色”水中发现了四种能在零度以下温度存活的不同酵母。
这类酵母仅存活在南极洲等极其寒冷的环境中，因此被认为是在奥茨死后的某个时候进入他体内的。
萨汉表示，基因分析显示，冰人肠道中的“DNA损伤水平与原始微生物非常相似”，这表明酵母在他死后不久就进入了他的身体。
“这些酵母陪伴奥茨走过了漫长的数千年旅程，”该研究的合著者弗兰克·迈克斯纳在一份声明中说道。
随后，科学家们在冰箱中培养了这种肠道酵母。
“只要你告诉任何人你有酵母，他们立刻就会问：我们能用它做面包吗？”萨汉说。
于是他们尝试制作一条酸面包。
“一开始失败了，”这位微生物学家坦言。
但经过三个月的努力，“我们做出了非常、非常棒的酸面包，”萨汉笑着说道。
当被问及科学家们是否考虑用这种酵母酿造啤酒时，他回答说：“已经列入计划了。”
这项研究为这种酵母找到了更严肃的潜在用途。
1991年发现这具木乃伊时，人们最初将其当作普通尸体处理。使用了一种名为苯酚的化学物质来防止身体滋生真菌。
但这种奇特的酵母能够分解苯酚，这意味着未来它可以帮助在受污染环境中分解这种化学物质，科学家们表示。
古代微生物组内部
酵母并非在奥茨体内发现的唯一令人惊讶的东西。
对他的微生物组的分析显示，有一种特殊的肠道细菌在现代人类中几乎不存在。
萨汉说，尽管这种细菌已经从工业化国家人们的胃部消失了，但在非洲和南美洲的部落中仍有发现。
意大利西马伦冰川中的木乃伊尸体在奥茨塔尔阿尔卑斯山被发现，距离奥地利边境92米。利奥波德·内库拉/西格玛/Getty Images
这种细菌还在奥地利哈尔施塔特盐矿中保存的3000年前的粪便中被发现——这是我们了解古代人类微生物组的仅有的几个窗口之一。
萨汉解释说，奥茨和这些青铜时代的盐矿工人比现代人摄入了更多的膳食纤维和全谷物。
这项发表在《微生物组》杂志上的研究称，它“揭示了冰人并非一个生物学上‘冰冻’的时间胶囊，而是一个复杂的生态系统”。
据路透社报道，此前的研究显示奥茨的最后一餐包括鹿肉、山羊肉以及小麦。此前的研究还表明，他去世时约45岁，身体状况良好，随身携带着铜斧、长弓、箭袋和匕首。
“他是一位访客，为我们了解过去提供了宝贵的见解，”迈克斯纳告诉路透社。
萨汉表示，现在判断酵母是否正在损害这具木乃伊还为时过早，呼吁开展更多研究。
未参与该研究的拉脱维亚有机合成研究所研究员尼古拉·奥斯科尔科夫告诉法新社，“冰人的微生物组并非‘冰冻’的”这一发现很有趣。
不过，此前曾在该木乃伊肠道中发现过古老真菌的奥斯科尔科夫警告称，酵母样本仅在2010年和2019年采集过。
这“几乎无法证明这些酵母在数千年间一直在繁殖”，他补充说，他认为这些酵母是“相对近期才在木乃伊体内定植的”。
2023年，科学家们确定奥茨的血统主要来自现今土耳其地区的农民，而且他的头部比最初认为的更秃，皮肤也更黑。
Scientists find yeast in frozen mummy’s guts, use it to make sourdough bread
June 3, 2026 / 9:41 AM EDT / CBS/AFP
Yeast has been growing in the guts of a frozen mummy called Oetzi the Iceman for thousands of years, scientists have discovered, telling AFP they used it to make a sourdough 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.
Since then, his stunningly well-preserved remains have been kept at the same temperature — minus six degrees Celsius — as his icy tomb.
This has allowed 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.
“What we didn’t expect to find was yeast,” lead study author Mohamed Sarhan of the Eurac Research institute in the Italian city of Bolzano told AFP.
The 5300-year-old mummy known as “Oetzi” is seen shortly after its arrival in the Archeology Museum in Bolzano in 1991. Simone Crepaldi/AP/dapd
“His body hosts living, metabolically capable organisms that are actively responding to their environment,” Sarhan told the Reuters news agency. “The cold-adapted yeasts are growing. Certain bacteria have colonized and persisted across his tissues for decades. The mummy is, in a very real sense, a living biological interface — a meeting point between the ancient world and the present, where microbes from 5,000 years ago coexist with organisms that arrived last decade.”
“Very good sourdough”
The scientists discovered four different yeasts that can survive sub-zero temperatures in Oetzi’s guts, skin and “brownish” water that melted off his body when he was partially unfrozen.
These kinds of yeast only live in very cold conditions such as Antarctica, so are believed to have entered Oetzi’s body at some point after he died.
Genetic analysis revealed “DNA damage levels very comparable to the original microbes” in the Iceman’s guts, suggesting the yeast entered his body soon after death, Sarhan said.
“These yeasts have accompanied Oetzi on his long journey through the millennia,” study co-author Frank Maixner said in a statement.
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.
So they tried to make a sourdough loaf.
“Initially it didn’t work,” the microbiologist admitted.
But after three months of effort “we had a very, very good sourdough,” Sarhan said with a laugh.
When asked if the scientists were considering using the yeast to brew beer, he responded: “It’s on the list.”
The study contained more serious possible uses for the yeast.
When the mummy was found in 1991, it was initially treated as a normal cadaver. A chemical called phenol was used to stop fungus from growing in the body.
However the strange yeast was able to eat the phenol, meaning that in the future it could help break down the chemical in contaminated environments, the scientists said.
Inside the ancient microbiome
The yeast was not the only surprising discovery in Oetzi’s body.
An analysis of his microbiome revealed a particular kind of a gut bacteria that is almost non-existent among modern humans.
Though gone from the stomachs of people in the industrialized world, the bacteria has been detected among tribes in Africa and South America, Sarhan said.
The mummified body of a man on the Similaun Glacier is discovered in the Ötztal Alps, Italy, 92 meters from the Austrian border. Leopold Nekula/Sygma via Getty Images
It has also been found in 3,000-year-old feces preserved in a salt mine in Hallstatt, Austria — which serves as one of the only other available views into the ancient human microbiome.
Oetzi and these Bronze Age salt miners ate more fiber and whole grain than modern-day people, Sarhan explained.
The study, published in the journal Microbiome, said it “reveals that the Iceman is not a biologically ‘frozen’ time-capsule but rather a complex ecosystem.”
Previous research revealed Oetzi’s last meals included deer and goat meat as well as wheat, Reuters reported. Previous research showed he was about age 45 when he died and was in good physical condition, carrying a copper ax, longbow, arrows and quiver and dagger.
“He is a visitor who provides us precious insights into the past,” Maixner told Reuter.
It is too early to say whether the yeast is harming the mummy, Sarhan said, calling for more research.
Nikolay Oskolkov, a researcher at the Latvian Institute of Organic Synthesis not involved in the study, told AFP it was interesting that “the Iceman’s microbiome is not ‘frozen’”.
However Oskolkov, who previously discovered ancient fungus in the mummy’s guts, cautioned that the yeast samples were only taken in 2010 and 2019.
This provides “very little evidence that the yeasts have been multiplying over millennia,” he said, adding that he believed they were “relatively recent colonists of the mummy’s body.”
In 2023, scientists determined that Oetzi was mostly descended from farmers from present day Turkey, and his head was balder and skin darker than what was initially thought.