Close to 1,500 years ago, indians living in what is now Quito, Ecuador buried their most revered dead in 16-meter-deep tombs. An ancient alcoholic beverage was commonly included in these burial vaults. Now, by examining the clay vessels used to ferment and store this brew, a team of South American researchers has managed to not only recover the microbes the indians used to ferment the ancient beverage, they've actually revived them...and they're unlike any species they've ever seen.
Between 200 and 800 AD, indian settlements thrived along the shores of a large, marshy lake that today is covered by Quito International Airport. When building crews first began surveying the area for the airport's construction, they discovered a number of gaping ancient tombs, similar to the one pictured up top. Each tomb was about 16 meters deep, contained roughly 20 carefully prepared bodies (recreated in this image), and was filled with clay pots — some of which were used to ferment an alcoholic beverage known as chicha.
It was the fermentation vessels that attracted Javier Carvajal Barriga, a yeast biologist at the Pontificia Universidad Católica del Ecuador in Quito. According to Scientific American:
Under the sterile conditions of his laboratory, [Carvajal] scratched away the surface layers from inside the fermentation vessels hoping to collect yeast trapped deep in the pottery's pores. Using a special method that he devised to humidify the desiccated cells, repair their damaged membranes, and jump-start their arrested metabolisms, he coaxed a community of yeasts, which had lain dormant in the entombed vessels since A.D. 680, back to life.
Carvajal and his team resurrected a number of different yeast strains, but not a one was saccharomyces cerivisiae — the yeast used in contemporary fermentation techniques. In fact, two of the strains were a new species entirely, and belonged to the genus Candida, many species of which are known to cause skin and vaginal infections. Carvajal's team named the new species C. theae, meaning "tea."
The decision to name the species "tea" would wind up being strangely appropriate. In 2010, on the other side of the globe from the researchers in South America, two cases of bottled tea were discovered to be clouded with contamination. When Taiwanese yeast taxonomist Ching-Fu Lee compared the genes of the yeast contaminating the tea with that of Carvajal's recently discovered C. theae, he found that the two strains matched. Lee, of course, contacted Carvajal immediately and the two collaborated to publish the paper that appears in the latest issue of International Journal of Food Microbiology.
So how could a long-lost yeast strain show up simultaneously on opposite ends of the world? "I don't think this is a beverage-related yeast, I think it is a human-related yeast," explains Carvajal. "We know now that there were contacts between Polynesians and South American peoples. [Polynesians] departed from Taiwan 6,000 years ago."
"We are using yeasts to track human migration and contacts. That is part of what we call 'microbiological archaeology.'"
The researchers' findings are published in the February issue of the International Journal of Food Microbiology.
Read more about the resurrected yeast (including a recipe for homemade chicha) over on SciAm.
Photos by R. Doublas Fields via SciAm