A group of Belgian scientists have not only identified the gene responsible for much of the flavor of beer and other alcoholic beverages, they’ve also engineered it for brewers.
By screening large numbers of yeast strains, researchers were able to identify the genes responsible for beer’s flavor.
“To our surprise, we identified a single mutation in the MDS3 gene, which codes for a regulator apparently involved in production of isoamyl acetate, the source of the banana-like flavor that was responsible for most of the pressure tolerance in this specific yeast strain,” said Johan Thevelein, Ph.D., an emeritus professor of Molecular Cell Biology at Katholieke Universiteit, and one of the researchers. His team pioneered the technology that identifies the genes responsible for commercially important traits in yeast.
Important to the study was finding the gene successful at creating flavor on a commercial scale. Modern, large-scale beer brewers use tall, cylindrical fermentation tanks compared to the traditional shorter vats. While the taller tanks are easier for brewing, it negatively impacts the beer’s taste. That’s because, when beer ferments, the yeast coverts 50% of the sugar in the mash to ethanol and the other 50% to carbon dioxide. But carbon dioxide pressurizes in the modern closed vessels, dampening flavor.
Using the gene editing technology CRISPR/Cas9, Thevelein and his team were able to engineer the MDS3 gene for other brewing strains, improving their tolerance of carbon dioxide pressure and improving the flavor.
“That demonstrated the scientific relevance of our findings, and their commercial potential,” Thevelein added in a statement.
“The mutation is the first insight into understanding the mechanism by which high carbon dioxide pressure may compromise beer flavor production,” said Thevelein, who noted that the MDS3 protein is likely a component of an important regulatory pathway that may play a role in carbon dioxide inhibition of banana flavor production, adding, “how it does that is not clear.”
The technology has also been successful in identifying genetic elements important for rose flavor production by yeast in alcoholic drinks, as well as other commercially important traits, such as glycerol production and thermotolerance.
The results of their study were published in Applied and Environmental Biology, the journal for the American Society for Microbiology.