Scientists Have Identified A Yeast Gene That
Gives Wine And Beer Special Flavors
When you taste a wine or beer that calls up the flavor of rose or honey think phenylethyl acetate; it’s a by-product of the yeast cells that turn sugar into alcohol to make wine and beer. Now, says Belgium microbiologists in a research paper, those flavors and more can be purposely developed in yeast strains using the latest gene-swapping scientific method.
The paper was published by mBio, a peer-reviewed journal of the century-old American Society for Microbiology (ASM). ASM covers a wide spectrum of individual microbiological research mainly for scientists to peruse. mBio is focused on more cutting-edge research of broader interest, and since winemaking has been a branch of microbiology ever since Louis Pasteur’s nineteenth century discovery that yeast is responsible for wine’s fermentation, the microbiology of wine is logically one of the areas for mBio to cover.
This particular study was led by Johan Thevelein working with Maria R. Foulquié-Moreno, each at the Center For Microbiology at VIB a Flanders-based life science institute. They applied high-throughput genomic analysis to study a hybrid strain of Saccharomyces cerevisiae, the yeast that ferments wine (and beer).
The researchers found “swaths of DNA” containing multiple genes with one causative gene linked to high production of the flavor compound phenylethyl acetate. They also identified the part of genes that are responsible for intense production of the flavor.
Commercial yeast breeding has given winemakers a measure of control over what used to be an often unreliable process. There are commercial yeasts to facilitate cool fermentation, to bring out fruitiness, to thrive in hostile pH environments, and so on. Yeast plays a critical flavor role in flavoring beer but in wine, the grapes are responsible for most of its flavor. Yet, when yeasts metabolize they alter grape flavors by adding secondary flavors of their own. Hence, after their gene discovery they set out to create yeast strains that produce desirable flavors.
Thevelein claims it’s already possible for microbiologists to create desirable flavors by selecting hybrid strains, but it is a time-consuming process. It’s also a risky process that works in the lab but doesn’t always work in the winery or brewery, where it can produce an off-fermentation. His research proves to him that the best way to engineer desirable traits in yeasts is to use the gene-swapping process known as CRSPR/Cas9.
Using CRSPR/Cas9 Thevelein and Foulquié were also able to increase the phenylethyl acetate flavor compound production in the parents of the hybrid genes they used for their experiment. They say the process creates indistinguishable yeast strains from other methods of yeast breeding, and it is expected to allow yeast breeders to pinpoint breeds that can be used to create certain flavor profiles from which wine and beer producers can select.
Who knows, the step might be that wine buyers can tell winemakers what flavors they would like in their wines when ordering on the futures market. Or maybe wine club members will be allowed to specify which flavors they would like when they place an order. Or maybe it’s nice to know about the genes but there might be no practicality in knowing.
It’s only wine, but it’s so good …
Remember to visit us at www.ggwc.com or call Frank @ 415.337.4083 to get some…