Two Novel Strains of Torulaspora delbrueckii Isolated from the Honey Bee Microbiome and Their Use in Honey Fermentation

Abstract

Yeasts are ubiquitous microbes found in virtually all environments. Many yeast species can ferment sugar into ethanol and CO 2 , and humans have taken advantage of these characteristics to produce fermented beverages for thousands of years. As a naturally abundant source of fermentable sugar, honey has had a central role in such fermentations since Neolithic times. However, as beverage fermentation has become industrialized, the processes have been streamlined, including the narrow and almost exclusive usage of yeasts in the genus Saccharomyces for fermentation. We set out to identify wild honey-or honey-bee-related yeasts that can be used in honey fermentation. Here, we isolated two strains of Torulaspora delbrueckii from the gut of a locally collected honey bee. Both strains were able to ferment honey sugar into mead but failed to metabolize more than a modest amount of wort sugar in trial beer fermentations. Further, the meads fermented by the T. delbrueckii strains displayed better sensory characteristics than mead fermented by a champagne yeast. The combination of T. delbrueckii and champagne yeast strains was also able to rapidly ferment honey at an industrial scale. Thus, wild yeasts represent a largely untapped reservoir for the introduction of desirable sensory characteristics in fermented beverages such as mead.

Evaluation of the potential of commercial non‐Saccharomyces yeast strains of Torulaspora delbrueckii and Lachancea thermotolerans in beer fermentation

“…This supports an earlier report that maltose fermentation was variable amongst different strains of T. delbrueckii , because not all strains possessed a maltose transporter and were able to synthesise maltase (Canonico et al , ). Similarly, wort fermentation in a previous study also revealed an extremely poor attenuation of maltose by T. delbrueckii YH178 and YH179, both of which eventually reached an alcohol content of approximately 0.3% (v/v) after 2 weeks of fermentation (Barry et al , ). In addition, the estimated ethanol contents based on the decreases in °Brix were significantly greater in Prelude (3.78, v/v) and Concerto (3.82, v/v)‐fermented beers than that of Biodiva‐fermented beers (1.33, v/v) (Table ).…”

Impact of fining agents on the volatile composition of sparkling mead

“…Mead is a traditional alcoholic beverage (alcoholic strength, by volume, between 8 and 18%) produced by the fermentation by yeasts of diluted honey. The production of mead has been the focus of numerous studies . However, few reports consider the volatile profile of mead and even fewer consider the production and characterisation of sparkling mead.…”

Biotechnological Importance of Torulaspora delbrueckii: From the Obscurity to the Spotlight

“…In the present review, we explored available information on the biochemical, genomic and phenotypic features of T. delbrueckii, with special emphasis on the aspects that make this yeast a promising biotechnological model to be exploited in a wide range of industries, Yeasts from the genus Torulaspora have been reported in a wide variety of habitats, such as fruits [6], insects [7,8], soils [9], soil invertebrates [10], plants [11,12], seawater [13], spoiled food [6] and malt environments [6], where yeast from other genera like Saccharomyces and Zygosaccharomyces may also be present [14,15]. Although not considered a human pathogen, the species T. delbrueckii can also be found as a clinical isolate [16].…”