(523d) The incredibly diverse microbiome of the Kombucha SCOBY

Kombucha is an acidic, effervescent, slightly alcoholic beverage, made by fermenting sweetened tea with a complex microbial consortia known as the SCOBY (Symbiotic Culture of Bacteria and Yeast). Originating in the far east and consumed for at least the past 2,000 years, until recently Kombucha has typically been home-brewed at relatively small scale.

Today, Kombucha is part of a consumer mega-trend towards fermented and minimally-processed products, and the Kombucha industry has consequently experienced explosive growth. The problem many producers face is how to scale-up while meeting specifications and tighter production schedules. This problem is exacerbated by a lack of knowledge concerning the microbial composition of the SCOBY, and how this relates to fermentation efficiency and product quality.

To address this knowledge gap, we collaborated with Kombucha Brewers International to survey the microbial complexity of commercial production SCOBY across the United States using microbiome sequencing approaches. Our results show that individual SCOBY contain upwards of a dozen yeast and bacterial genera, highlighting the microbial complexity of Kombucha production. Clustering of the microbial profiles revealed five main SCOBY types discriminated by their dominant yeast and bacterial genera. In laboratory-scale fermentations, representative SCOBY from these groups differed in the rate at which they acidified sweetened tea, and produced kombucha with differing chemical compositions.

These results provide the first large-scale insight into the diversity of Kombucha SCOBY and reveal a level of interchangeability between different microbial genera to achieve similar function. Ongoing research is using this framework to ask how individual yeast and bacterial species contribute to Kombucha style, and to what extent an individual SCOBY reflects the production environment in which it is used.