Comparative physiology and fermentation performance of Saaz and Frohberg lager yeast strains and the parental species Saccharomyces eubayanus. Issue 7 (29th June 2013)

• Record Type: Journal Article
• Authors: Gibson, Brian R.; Storgårds, Erna; Krogerus, Kristoffer; Vidgren, Virve
• Is Part Of: Yeast. Volume 30:Issue 7(2013:Jul.)
• Page Start: 255
• Page End: 266
• Publication Date: 2013-06-29
• Subjects: Yeast -- Periodicals; Yeasts -- Periodicals; Yeasts -- genetics -- Periodicals; Electronic journals; 547
• DOI: 10.1002/yea.2960
• Languages: English
• ISSNs: 0749-503X

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>Two distinct genetic groups (Saaz and Frohberg) exist within the hybrid <italic>Saccharomyces pastorianus</italic> (<italic>S</italic>. <italic>cerevisiae</italic> × <italic>S</italic>. <italic>eubayanus</italic>) taxon. However, physiological/technological differences that exist between the two groups are not known. Fermentative capability of the parental <italic>S</italic>. <italic>eubayanus</italic> has likewise never been studied. Here, 58 lager strains were screened to determine which hybrid group they belonged to, and selected strains were characterized to determine salient characteristics. In 15 °P all‐malt wort fermentations at 22 °C, Frohberg strains showed greater growth and superior fermentation (80% apparent attenuation, 6.5% alcohol by volume in 3–4 days) compared to all other strains and maintained highest viability values (>93%). Fermentation with <italic>S</italic>. <italic>eubayanus</italic> was poor at the same temperature (33% apparent attenuation, 2.7% alcohol by volume at 6 days and viability reduced to 75%). Saaz strains and <italic>S</italic>. <italic>eubayanus</italic> were the least sensitive to cold (10 °C), though this did not translate to greater fermentation performance. Fermentation with <italic>S</italic>. <italic>eubayanus</italic> was poor at 10 °C but equal to or greater than that of the Saaz strains. Performance of Saaz yeast/<italic>S</italic>. <italic>eubayanus</italic> was limited by an inability to use wort maltotriose. [<sup>14</sup>C]‐Maltotriose transport assays also showed negligible activity in these strains (≤0.5 µmol min<sup>−1</sup> g<sup>−1</sup> dry yeast). Beers from Saaz fermentations were characterized by two‐ to sixfold lower production of the flavour compounds methyl butanol, ethyl acetate and 3‐methylbutyl acetate compared to Frohberg strains. Higher alcohol and ester production by <italic>S</italic>. <italic>eubayanus</italic> was similar to that of Frohberg strains. Copyright © 2013 John Wiley & Sons, Ltd.</p> </abstract>