Ancient fermented food has been studied based on recipes, residue analysis, and ancient-DNA techniques and reconstructed using modern domesticated yeast. Here, we present a novel approach based on our hypothesis that enriched yeast populations in fermented beverages could have become the dominant species in storage vessels and their descendants could be isolated and studied today. We developed a pipeline of yeast isolation from clay vessels and screened for yeast cells in beverage-related and non-beverage-related ancient vessels and sediments from several archaeological sites. We found that yeast cells could be successfully isolated specifically from clay containers of fermented beverages. The findings that genotypically the isolated yeasts are similar to those found in traditional African beverages and phenotypically they grow similar to modern beer-producing yeast strongly suggest that they are descendants of the original fermenting yeast. These results demonstrate that modern microorganisms can serve as a new tool in bio-archaeology research. IMPORTANCE So far, most of the study of ancient organisms has been based mainly on the analysis of ancient DNA. Here we show that it is possible to isolate and study microorganisms-yeast in this case-from ancient pottery vessels used for fermentation. We demonstrate that it is highly likely that these cells are descendants of the original yeast strains that participated in the fermentation process and were absorbed into the clay matrix of the pottery vessels. Moreover, we characterized the isolated yeast strains, their genomes, and the beer they produced. These results open new and exciting avenues in the study of domesticated microorganisms and contribute significantly to the fields of bio- and experimental archaeology that aim to reconstruct ancient artifacts and products.
Bibliographical noteFunding Information:
We thank the Israel Antiquities Authority and the Israel Nature and Parks Authority for assistance and the staff and team members of the Tell es-Safi/Gath Archaeological Project (Bar-Ilan University) and the Ramat Rachel Archaeological Project (Tel Aviv University). Thanks to G. Litani, D. Barkan, and D. Abu-Salah, excavators of the site at Ha-Masger St. Tel Aviv. We also thank the members of the Beer Judge Certification Program (BJCP) Omer Basha, Noam Shalev, Ephraim Greenblat, and Roi Krispin and the beer experts and brewers Shmuel Naky, Eyal Grossman, Ulrike Genz, Franz Pozelt, and Yisrael Atlow for tasting and evaluating our beers. We thank the team of the Interdepartmental Core Unit of the Hebrew University at the Hadassah Ein Karem campus, Edi Berenshtein for assistance with the electron microscopy, and Abed Nasereddin and Idit Shiff for NGS sequencing. We also thank Marina Faerman, Philipp Stockhammer, and Christina Warinner for critical reading of the manuscript and Ayelet El-Boher, Sharon Ben-Hur, and Maayan Margulis for technical assistance. Last, we thank the Kedma winery, Kfar Uria, Israel, for supplying fragments of a wine clay container that had been unused for the last 2 years.
© 2019 Aouizerat et al.
- Ancient fermented food and beverages
- Ancient pottery vessels
- Experimental archaeology