Major contribution of the Ehrlich pathway for 2‐phenylethanol/rose flavor production in Ashbya gossypii. Issue 6 (27th June 2014)

• Record Type: Journal Article
• Authors: Ravasio, Davide; Wendland, Jürgen; Walther, Andrea
• Is Part Of: FEMS yeast research. Volume 14:Issue 6(2014)
• Page Start: 833
• Page End: 844
• Publication Date: 2014-06-27
• Subjects: Yeast -- Periodicals; Yeasts -- Periodicals; 579.562
• DOI: 10.1111/1567-1364.12172
• Languages: English
• ISSNs: 1567-1356

Abstract

<abstract abstract-type="main" id="fyr12172-abs-0001"> <title>Abstract</title> <p>Aroma alcohols of fermented food and beverages are derived from fungal amino acids catabolism via the Ehrlich pathway. This linear pathway consists of three enzymatic reactions to form fusel alcohols. Regulation of some of the enzymes occurs on the transcriptional level via Aro80. The riboflavin overproducer <italic>Ashbya gossypii</italic> produces strong fruity flavours in contrast to its much less aromatic relative <italic>Eremothecium cymbalariae</italic>. Genome comparisons indicated that <italic>A. gossypii</italic> harbors genes for aromatic amino acid catabolism (<italic>ARO8a</italic>, <italic> ARO8b</italic>, <italic> ARO10</italic>, and <italic>ARO80</italic>) while <italic>E. cymbalariae</italic> only encodes <italic>ARO8a</italic> and thus lacks major components of aromatic amino acid catabolism. Volatile compound (VOC) analysis showed that both <italic>Eremothecium</italic> species produce large amounts of isoamyl alcohol while <italic>A. gossypii</italic> also produces high levels of 2‐phenylethanol. Deletion of the <italic>A. gossypii ARO</italic>‐genes did not confer any growth deficiencies. However, <italic>A. gossypii ARO</italic>‐mutants (except <italic>Agaro8a</italic>) were strongly impaired in aroma production, particularly in the production of the rose flavour 2‐phenylethanol. Conversely, overexpression of <italic>ARO80</italic> via the <italic>AgTEF1</italic> promoter resulted in 50% increase in VOC production. Together these data indicate that <italic>A. gossypii</italic> is a very potent flavour producer and that amongst the non‐<italic>Saccharomyces</italic> biodiversity strains can be identified that could provide positive sensory properties to fermented beverages.</p> </abstract>