Today’s tall cylindrical fermentation tanks that have replaced shorter brewery vessels in the past tended to negatively affect the taste of the resulting beer – but now scientists have stepped in to improve the taste of our drink.
These tall tanks can produce more beer for less money – they’re easier to fill, empty and clean – but their widespread adoption also means too much pressure from the carbon dioxide produced during fermentation, which affects taste.
The researchers started by identifying its strains Saccharomyces cerevisiae yeast that was particularly CO2-resistant, focusing on the production of isoamyl acetate that gives beer its fruity banana-like taste.
After finding a particularly potent strain, the team used a whole-genome sequence analysis to understand what made it so capable of retaining its fruity flavor even under the pressure of modern fermentation tanks.
“To our surprise, we identified a single mutation in the MDS3 gene, which encodes a regulator apparently involved in the production of isoamyl acetate, the source of the banana-like flavor that was responsible for most of the stress tolerance in this particular strain. dough. says molecular biologist Johan Thevelein, from the Katholieke Universiteit Leuven in Belgium.
With this discovery, the researchers were then able to use the CRISPR/Cas9 gene editing technique to create the same mutation in other yeast strains. After treatment, these strains could tolerate CO better2 they press and retain their flavor better.
Down the line, many yeast strains could be modified in the same way, leading to fuller-flavored beers when poured.
So far, it does not appear that other characteristics of the yeast strain are affected by the genetic modifications.
“The mutation is the first insight into understanding the mechanism by which high carbon dioxide pressure can compromise beer flavor production,” says Thevelein.
Until now, it was not clear how high CO is2 The pressure has an impact on the beer’s flavor on a molecular level, although the end results in terms of fruitiness were easily palatable.
In the future, the researchers want to conduct experiments with even higher CO2 strains to see if different genes are identified. A number of other genes showed promise in this study as well, although MDS3 was the dominant one.
The same gene identification technology has also been used in the past to highlight other important yeast traits, including glycerol production (a sugar alcohol that adds flavor) and tolerance to elevated temperatures.
The authors are upfront about the fact that the work was supported by a brewing company, which hopes to make use of the technology in a patent.
While other beer brands may miss out on the technology, the study demonstrates the potential benefits of applying CRISPR to tailor the yeast’s talents for a great drop.
“This work demonstrates the powerful potential of multigene analysis and targeted genetic modification to generate industrial beer yeast strains with specifically improved traits,” the researchers write in their published paper.
The research has been published in Applied and Environmental Microbiology.