Fruits of their labour: Biotransformation reactions of yeasts during brewery fermentation

Natalia Svedlund, Simon Evering, Brian Gibson, Kristoffer Krogerus (Corresponding Author)

Research output: Contribution to journalReview Articlepeer-review

15 Citations (Scopus)
44 Downloads (Pure)


Abstract: There is a growing appreciation for the role that yeast play in biotransformation of flavour compounds during beverage fermentations. This is particularly the case for brewing due to the continued popularity of aromatic beers produced via the dry-hopping process. Here, we review the current literature pertaining to biotransformation reactions mediated by fermentative yeasts. These reactions are diverse and include the liberation of thiols from cysteine or glutathione-bound adducts, as well as the release of glycosidically bound terpene alcohols. These changes serve generally to increase the fruit and floral aromas in beverages. This is particularly the case for the thiol compounds released via yeast β-lyase activity due to their low flavour thresholds. The role of yeast β-glucosidases in increasing terpene alcohols is less clear, at least with respect to fermentation of brewer’s wort. Yeast acetyl transferase and acetate esterase also have an impact on the quality and perceptibility of flavour compounds. Isomerization and reduction reactions, e.g. the conversion of geraniol (rose) to β-citronellol (citrus), also have potential to alter significantly flavour profiles. A greater understanding of biotransformation reactions is expected to not only facilitate greater control of beverage flavour profiles, but also to allow for more efficient exploitation of raw materials and thereby greater process sustainability. Key points: • Yeast can alter and boost grape- and hop-derived flavour compounds in wine and beer • β-lyase activity can release fruit-flavoured thiols with low flavour thresholds • Floral and citrus-flavoured terpene alcohols can be released or interconverted.

Original languageEnglish
Pages (from-to)4929–4944
Number of pages16
JournalApplied Microbiology and Biotechnology
Issue number13-16
Publication statusPublished - Aug 2022
MoE publication typeA2 Review article in a scientific journal


  • Beverages
  • Biotransformation
  • Fermentation
  • Polyfunctional thiol
  • Terpene
  • Yeast
  • β-glucosidase
  • β-lyase
  • Alcohols/metabolism
  • Fruit/metabolism
  • Flavoring Agents/metabolism
  • Yeasts/metabolism
  • Terpenes/metabolism
  • Beer
  • Saccharomyces cerevisiae/metabolism
  • Lyases/metabolism
  • Sulfhydryl Compounds/metabolism


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