Real life applications of gene sequencing in… alcohol?

The average college student – and the stereotypical middle-aged man – will both, from time to time, enjoy the occasional ice-cold beer. The average college student and stereotypicalmiddle-aged men, however, probably have not thought about how having a favourite type of beer inherently means having a favorite strain of yeast and a preferred process of fermentation. Confused? Allow me to explain.

The alcohol in some alcoholic beverages, including beer, comes from a key process in industrial microbiology called fermentation, in which oxygen-deprived bacteria or fungi break down carbohydrates into alcohols and acids. Yeast produces ethanol (not to be confused with methanol, which is unsafe for consumption), but fermentation is used to produce foods and non-alcoholic beverages such as kombucha, yogurt and even xanthan gum, a substance used in the production of cosmetics. Another product of fermentation, carbon dioxide, is used in SodaStream machines to make carbonated drinks, and if you’ve ever made bread, you’ve guessed it — carbon dioxide made the dough rise.

I know all of that sounds disgusting, but fermentation has been utilized for a long time and scientists have been studying it for centuries. One of the oldest known records of alcohol produced by fermentation, a vase with wine remains, is 7,000 years old. Prominent scientists such as Antoni Van Leeuwenhoek (18th century microbiologist) and Antoine Lavoisier (18th century chemist) were pioneers in the study of the structure of yeast and the chemical reactions in fermentation. Nowadays, USask has its very own scientists studying how different strains (or subtypes) of yeast and the conditions they’re treated in produce different flavors and aromas of beer.

Josefina Nelson is a Saskatchewan-born geologist, geochemist and third year PhD candidate in the College of Agriculture and Bioresources, working in the Eskiw Lab. Her research, funded by Mitacs and the Agricultural Development Fund, is focused on linking yeast genetics to flavours in local beer production. Despite her background in geology and her initial aversion to a PhD, Nelson claims she “got totally taken in by the curiosity of the whole system.” She is also in a Mitacs industrial partnership with 21st Street Brewery which gives her “[a] sort of play between academia and industry.”

“This is science — just because we’ve been doing it for thousands of years doesn’t mean people didn’t know what they were doing.” said Nelson. 

In the later stages of the beer-making process, wort (the product of earlier stages of the process, and the source of sugar for yeast) is fermented in large-scale bioreactors – big vessels designed to allow the yeast to ferment. Samples taken from these bioreactors have their metabolite (products of metabolic reactions) composition studied to determine when they were made, and the expression of the gene coding for these products is determined by analyzing the yeast’s RNA sequence (the DNA’s “chemical cousin” and the template for protein synthesis). Nelson is employing modern molecular biology techniques to study how the presence of certain genes, which determine the products made throughout the fermentation process, give rise to different flavors of beer across multiple strains of yeast. She also says some techniques overlap in the mechanical processes she used during her geology research and her current research, like mass spectrometry.

Nelson is also a member of the non-profit organization Pink Boots Society, whose mission is to support and encourage women and non-binary individuals in the fermented/alcohol beverage industry to advance their careers through further education. They provide scholarships and seminars about the industry to members and interestingly, they brew special collaboration beers to honor International Women’s Day every March 8th.

Nelson has aspirations of revolutionizing the beer industry with her research: “One of the major parts of [the project] is to provide a handbook to the brewers on how to treat their yeast before and during fermentation.” She aims to figure out the pre-fermentation conditions that lead to the expression of specific genes at certain times, thus leading to one flavor or aroma. This could mean that in the future, brewers (and Genetics PhD students) would be able to experiment with different conditions to come up with novel beer flavors. Nelson hopes to achieve this “starting with 21st Street Brewery!”, in which Nelson works under Brewmaster Casey Murray. 21st Street Brewery is located in Downtown Saskatoon, directly under Winston’s English Pub.

If beer is not your thing, don’t lose hope! Maybe you prefer your pre-fermented yeast to be slightly more acidic or at a lower temperature than standard — we’ll leave it to the scientists to come up with novel uses for this simple but exciting process that has been around for centuries.