Abstract
The yeast strains of the Saccharomyces sensu stricto complex involved in beer production are a heterogeneous group whose genetic and genomic features are not adequately determined. Thus, the aim of the present study was to provide a genetic characterization of selected group of commercially available brewing yeasts both ale top-fermenting and lager bottom-fermenting strains. Molecular karyotyping revealed that the diversity of chromosome patterns and four strains with the most accented genetic variabilities were selected and subjected to genome-wide array-based comparative genomic hybridization (array-CGH) analysis. The differences in the gene copy number were found in five functional gene categories: (1) maltose metabolism and transport, (2) response to toxin, (3) siderophore transport, (4) cellular aldehyde metabolic process, and (5) L-iditol 2-dehydrogenase activity (p < 0.05). In the Saflager W-34/70 strain (Fermentis) with the most affected array-CGH profile, loss of aryl-alcohol dehydrogenase (AAD) gene dosage correlated with an imbalanced redox state, oxidative DNA damage and breaks, lower levels of nucleolar proteins Nop1 and Fob1, and diminished tolerance to fermentation-associated stress stimuli compared to other strains. We suggest that compromised stress response may not only promote oxidant-based changes in the nucleolus state that may affect fermentation performance but also provide novel directions for future strain improvement.Electronic supplementary materialThe online version of this article (doi:10.1007/s12192-016-0710-8) contains supplementary material, which is available to authorized users.
Highlights
Beer, one of the most common alcoholic beverages consumed worldwide, is produced by the fermentation of sugars into alcohol by the action of yeasts
Lager yeasts can be further divided into two genetic groups that differ in fermentation performance, sugar utilization and adaptation to growth at low temperature (Dunn and Sherlock 2008; Gibson et al 2013)
Regions with variations in gene copy number were revealed, and we found that aryl-alcohol dehydrogenase gene dosage correlated with intracellular redox equilibrium, genetic stability, and the nucleolar state, which may modulate tolerance to stress stimuli during fermentation conditions in brewing yeasts
Summary
One of the most common alcoholic beverages consumed worldwide, is produced by the fermentation of sugars into alcohol by the action of yeasts. Brewing yeasts are typically divided into two groups, ale brewing yeasts and lager brewing yeasts, according to their use for the production of ale and lager beers, respectively (Gibson and Liti 2015; Kodama et al 2006; Wendland 2014). It seems worthwhile to monitor genetic and genomic features of brewing yeast strains, especially that their genomes are dynamic and may undergo rearrangements and gene amplification in response to stresses experienced during the brewing process (James et al 2008)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
