scholarly journals Lager-brewing yeasts in the era of modern genetics

2019 ◽  
Vol 19 (7) ◽  
Author(s):  
Arthur R Gorter de Vries ◽  
Jack T Pronk ◽  
Jean-Marc G Daran

ABSTRACT The yeast Saccharomyces pastorianus is responsible for the annual worldwide production of almost 200 billion liters of lager-type beer. S. pastorianus is a hybrid of Saccharomyces cerevisiae and Saccharomyces eubayanus that has been studied for well over a century. Scientific interest in S. pastorianus intensified upon the discovery, in 2011, of its S. eubayanus ancestor. Moreover, advances in whole-genome sequencing and genome editing now enable deeper exploration of the complex hybrid and aneuploid genome architectures of S. pastorianus strains. These developments not only provide novel insights into the emergence and domestication of S. pastorianus but also generate new opportunities for its industrial application. This review paper combines historical, technical and socioeconomic perspectives to analyze the evolutionary origin and genetics of S. pastorianus. In addition, it provides an overview of available methods for industrial strain improvement and an outlook on future industrial application of lager-brewing yeasts. Particular attention is given to the ongoing debate on whether current S. pastorianus originates from a single or multiple hybridization events and to the potential role of genome editing in developing industrial brewing yeast strains.

Author(s):  
Fabrizio Iattici ◽  
Martina Catallo ◽  
Lisa Solieri

Beer is a fermented beverage with a history as old as human civilization and its productive process has been spread all around the world becoming unique in every country and iconic of entire populations. Ales and lagers are by far the most common beers; however, the combination of raw materials, manufacture techniques and aroma profiles are almost infinite, so it is not surprising to notice that there is a large amount of different beer styles, each of them with unique characteristics. Nowadays, diversification is becoming increasingly important in the brewing market and the brewers are continuously interested in improving and extending the already wide range of products, especially in craft brewery. One of the major components that can have a deep impact on the final product is yeast, since it is able to convert carbohydrates in wort, especially maltose and maltotriose, into ethanol, carbon dioxide and other minor aroma-active compounds. Saccharomyces cerevisiae (top‐fermenting yeasts used to produce ales) and Saccharomyces pastorianus (cryotolerant bottom‐fermenting hybrids between S. cerevisiae and Saccharomyces eubayanus responsible for the fermentation of lagers) are most used in breweries. However, an increasing number of different yeast starter cultures are commercially available, to improve the production efficiency also at relative low temperatures and to obtain desirable and diversified aroma profiles avoiding undesired compounds. Four main genetic engineering-free trends are becoming popular in craft brewing yeast development: 1) the research for novel reservoirs as source of new performant S. cerevisiae yeasts; 2) the creation of synthetic hybrids between S. cerevisiae and Saccharomyces non-cerevisiae in order to mimic lager yeasts by expanding their genetic background; 3) the exploitation of evolutionary engineering approaches; 4) the usage of non-Saccharomyces yeasts either in co-coculture or in sequential fermentation with S. cerevisiae. In the present work we summarized pro and contra of these approaches and provided an overview on the most recent advances on how brewing yeast genome evolved and domestication took place. Finally, we delineated how the correlations maps between genotypes and relevant brewing phenotypes can assist and further improve the search for novel craft beer starter yeasts.


2019 ◽  
Vol 5 (1) ◽  
pp. eaav1869 ◽  
Author(s):  
EmilyClare P. Baker ◽  
David Peris ◽  
Ryan V. Moriarty ◽  
Xueying C. Li ◽  
Justin C. Fay ◽  
...  

A growing body of research suggests that the mitochondrial genome (mtDNA) is important for temperature adaptation. In the yeast genusSaccharomyces, species have diverged in temperature tolerance, driving their use in high- or low-temperature fermentations. Here, we experimentally test the role of mtDNA in temperature tolerance in synthetic and industrial hybrids (Saccharomyces cerevisiae×Saccharomyces eubayanusorSaccharomyces pastorianus), which cold-brew lager beer. We find that the relative temperature tolerances of hybrids correspond to the parent donating mtDNA, allowing us to modulate lager strain temperature preferences. The strong influence of mitotype on the temperature tolerance of otherwise identical hybrid strains provides support for the mitochondrial climactic adaptation hypothesis in yeasts and demonstrates how mitotype has influenced the world’s most commonly fermented beverage.


Fermentation ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 107
Author(s):  
Javier Porcayo Loza ◽  
Anna Chailyan ◽  
Jochen Forster ◽  
Michael Katz ◽  
Uffe Hasbro Mortensen ◽  
...  

Approximately 25% of all carbohydrates in industrial worts are poorly, if at all, fermented by brewing yeast. This includes dextrins, β-glucans, arabinose, xylose, disaccharides such as isomaltose, nigerose, kojibiose, and trisaccharides such as panose and isopanose. As the efficient utilization of carbohydrates during the wort’s fermentation impacts the alcohol yield and the organoleptic traits of the product, developing brewing strains with enhanced abilities to ferment subsets of these sugars is highly desirable. In this study, we developed Saccharomyces pastorianus laboratory yeast strains with a superior capacity to grow on isomaltose and panose. First, we designed a plasmid toolbox for the stable integration of genes into lager strains. Next, we used the toolbox to elevate the levels of the α-glucoside transporter Agt1 and the major isomaltase Ima1. This was achieved by integrating synthetic AGT1 and IMA1 genes under the control of strong constitutive promoters into defined genomic sites. As a result, strains carrying both genes showed a superior capacity to grow on panose and isomaltose, indicating that Ima1 and Agt1 act in synergy to consume these sugars. Our study suggests that non-GMO strategies aiming to develop strains with improved isomaltose and panose utilization could include identifying strains that overexpress AGT1 and IMA1.


2018 ◽  
Author(s):  
EmilyClare P. Baker ◽  
David Peris ◽  
Ryan V. Moriarty ◽  
Xueying C. Li ◽  
Justin C. Fay ◽  
...  

AbstractA growing body of research suggests that the mitochondrial genome (mtDNA) is important for temperature adaptation. In the yeast genusSaccharomyces, species have diverged in temperature tolerance, driving their use in high or low temperature fermentations. Here we experimentally test the role of mtDNA in temperature tolerance in synthetic and industrial hybrids (Saccharomyces cerevisiaexSaccharomyces eubayanus, orSaccharomyces pastorianus), which cold-brew lager beer. We find that the relative temperature tolerances of hybrids correspond to the parent donating mtDNA, allowing us to modulate lager strain temperature preferences. The strong influence of mitotype on the temperature tolerance of otherwise identical hybrid strains provides support for the mitochondrial climactic adaptation hypothesis in yeasts and demonstrates how mitotype has influenced the world's most commonly fermented beverage.One Sentence SummaryMitochondrial genome origin affects the temperature tolerance of synthetic and industrial lager-brewing yeast hybrids.


2020 ◽  
Author(s):  
Diego Bonatto

AbstractYeasts from the species Saccharomyces cerevisiae (ale yeast) and Saccharomyces pastorianus (lager yeast) are the main component of beer fermentation. It is known that different beer categories depend on the use of specific ale or lager strains, where the yeast imprint its distinctive fermentative profile to the beer. Despite this, there are no studies reporting how diverse, rich, and homogeneous the beer categories are in terms of commercially available brewing yeast strains. In this work, the diversity, richness, and evenness of different beer categories and commercial yeast strains available for brewing were evaluated by applying quantitative concepts of ecology analysis in a sample of 121,528 beer recipes. For this purpose, the frequency of ale or lager and dry or liquid yeast formulations usage was accessed and its influence in the fermentation temperature, attenuation profile, and number of recipes for a beer category were analyzed. The results indicated that many beer categories are preferentially fermented with dry yeast strains formulations instead of liquid yeasts, despite considering the high number of available liquid yeast formulations. Moreover, ale dry strains are preferentially used for lager brewing. The preferential use of specific yeast formulations drives the diversity, richness, and evenness of a beer category, showing that many yeast strains are potentially and industrially underexplored.


Beverages ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 3 ◽  
Author(s):  
Fabrizio Iattici ◽  
Martina Catallo ◽  
Lisa Solieri

Beer is a fermented beverage with a history as old as human civilization. Ales and lagers are by far the most common beers; however, diversification is becoming increasingly important in the brewing market and the brewers are continuously interested in improving and extending the range of products, especially in the craft brewery sector. Fermentation is one of the widest spaces for innovation in the brewing process. Besides Saccharomyces cerevisiae ale and Saccharomyces pastorianus lager strains conventionally used in macro-breweries, there is an increasing demand for novel yeast starter cultures tailored for producing beer styles with diversified aroma profiles. Recently, four genetic engineering-free approaches expanded the genetic background and the phenotypic biodiversity of brewing yeasts and allowed novel costumed-designed starter cultures to be developed: (1) the research for new performant S. cerevisiae yeasts from fermented foods alternative to beer; (2) the creation of synthetic hybrids between S. cerevisiae and Saccharomyces non-cerevisiae in order to mimic lager yeasts; (3) the exploitation of evolutionary engineering approaches; (4) the usage of non-Saccharomyces yeasts. Here, we summarized the pro and contra of these approaches and provided an overview on the most recent advances on how brewing yeast genome evolved and domestication took place. The resulting correlation maps between genotypes and relevant brewing phenotypes can assist and further improve the search for novel craft beer starter yeasts, enhancing the portfolio of diversified products offered to the final customer.


2017 ◽  
Vol 8 ◽  
Author(s):  
Anja Brickwedde ◽  
Marcel van den Broek ◽  
Jan-Maarten A. Geertman ◽  
Frederico Magalhães ◽  
Niels G. A. Kuijpers ◽  
...  

1991 ◽  
Vol 37 (5) ◽  
pp. 397-403 ◽  
Author(s):  
Hiroshi Kuriyama ◽  
Itaru Umeda ◽  
Harumi Kobayashi

Asexual yeast flocculation was studied using strong flocculents of Saccharomyces cerevisiae. The inhibitory effect of cations on flocculation is considered to be caused by competition between those cations and Ca2+ at the binding site of the Ca2+-requiring protein that is involved in flocculation. Inhibition of flocculation by various cations occurred in the following order: La3+, Sr2+, Ba2+, Mn2+, Al3+, and Na+. Cations such as Mg2+, Co2+, and K+ promoted flocculation. This promoting effect may be based on the reduction of electrostatic repulsive force between cells caused by binding of these cations anionic groups present on the cell surface. In flocculation induced by these cations, trace amounts of Ca2+ excreted on the cell surface may activate the corresponding protein. The ratio of Sr2+/Ca2+ below which cells flocculated varied among strains: for strains having the FLO5 gene, it was 400 to 500; for strains having the FLO1 gene, about 150; and for two alcohol yeast strains, 40 to 50. This suggests that there are several different types of cell surface proteins involved in flocculation in different yeast strains. Key words: yeast, flocculation, protein, cation, calcium.


2021 ◽  
Author(s):  
Haina Huang ◽  
Melissa Parker ◽  
Katrin Karbstein

AbstractRibosome assembly is an intricate process, which in eukaryotes is promoted by a large machinery comprised of over 200 assembly factors (AF) that enable the modification, folding, and processing of the ribosomal RNA (rRNA) and the binding of the 79 ribosomal proteins. While some early assembly steps occur via parallel pathways, the process overall is highly hierarchical, which allows for the integration of maturation steps with quality control processes that ensure only fully and correctly assembled subunits are released into the translating pool. How exactly this hierarchy is established, in particular given that there are many instances of RNA substrate “handover” from one highly related AF to another remains to be determined. Here we have investigated the role of Tsr3, which installs a universally conserved modification in the P-site of the small ribosomal subunit late in assembly. Our data demonstrate that Tsr3 separates the activities of the Rio kinases, Rio2 and Rio1, with whom it shares a binding site. By binding after Rio2 dissociation, Tsr3 prevents rebinding of Rio2, promoting forward assembly. After rRNA modification is complete, Tsr3 dissociates, thereby allowing for recruitment of Rio1. Inactive Tsr3 blocks Rio1, which can be rescued using mutants that bypass the requirement for Rio1 activity. Finally, yeast strains lacking Tsr3 randomize the binding of the two kinases, leading to the release of immature ribosomes into the translating pool. These data demonstrate a role for Tsr3 and its modification activity in establishing a hierarchy for the function of the Rio kinases.


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