Discovering the indigenous microbial communities associated with the natural fermentation of sap from the cider gum Eucalyptus gunnii

Over the course of human history and in most societies, fermented beverages have played a unique role due to their economic and cultural importance. In Australia before the arrival of the first Europeans, Aboriginal people produced several fermented drinks including mangaitch from flowering cones of a banksia plant and way-a-linah from Eucalyptus tree sap. Numerous microorganisms, including fungi, yeast and bacteria, present on the surface of fruits and grains, are responsible for the conversion of the sugar present in these materials into ethanol. Here we describe native microbial communities associated with the spontaneous fermentation of sap from the cider gum Eucalyptus gunnii, a Eucalyptus tree native to the remote Central Highlands of Tasmania. Amplicon-based phylotyping showed numerous microbial species in cider gum samples, with fungal species differing greatly to those associated with winemaking. Phylotyping also revealed several fungal sequences which do not match known fungal genomes suggesting novel yeast species. These findings highlight the vast microbial diversity associated to the Australian Eucalyptus gunnii and the native alcoholic beverage way-a-linah.