Microbiologists improve taste of beer

Belgian investigators have improved the flavor of contemporary beer by identifying and engineering a gene that is responsible for much of the flavor of beer and some other alcoholic drinks. The research appears in Applied and Environmental Microbiology.

-For centuries, beer was brewed in open, horizontal vats. But in the 1970s, the industry switched to using large, closed vessels, which are much easier to fill, empty, and clean, enabling brewing of larger volumes and reducing costs. However, these modern methods produced inferior quality beer, due to insufficient flavor production.

During fermentation, yeast converts 50 percent of the sugar in the mash to ethanol, and the other 50 percent to carbon dioxide. The problem: the carbon dioxide pressurizes these closed vessels, dampening flavor.

Johan Thevelein, Ph.D., an emeritus professor of Molecular Cell Biology at Katholieke Universiteit, and his team had pioneered technology for identifying genes responsible for commercially important traits in yeast. They applied this technology to identify the gene(s) responsible for flavor in beer, by screening large numbers of yeast strains to evaluate which did the best job of preserving flavor under pressure.

They focused on a gene for a banana-like flavor "because it is one of the most important flavors present in beer, as well as in other alcoholic drinks," said Thevelein, who is also founder of NovelYeast, which collaborates with other companies in industrial biotechnology.

Thevelein and coworkers then used CRISPR/Cas9, a gene editing technology, to engineer this mutation in other brewing strains, which similarly improved their tolerance of carbon dioxide pressure, enabling full flavor. "That demonstrated the scientific relevance of our findings, and their commercial potential," said Thevelein.

Image source: Souffriau et al. (2022), Applied and Environmental Microbiology.