Craft beers have revolutionized the beer industry. In 2018, the craft beer market made up 20% of the sales of beer in the United States, totaling over 26 billion dollars and experiencing significant growth during a period when many traditional breweries are reporting losses or shrinkage in their market values (Gaille, 2019). Survival in an increasingly competitive market is reliant on the ability to develop novel products that match the ever-evolving tastes of consumers. I worked with the Three Roads Brewing Company of Farmville and Lynchburg, Virginia to meet this goal using molecular biology. My institution has a preexisting relationship with Three Roads Brewery, as my research advisor has been doing similar but less intensive projects to teach students about the fundamentals of genetic engineering. The Brewmaster uses a strain of baker's yeast (Saccharomyces cerevisiae) called S-11 to generate a French Saison beer, a highly carbonated pale ale. My research worked to modify the S-11 strain to generate a French Saison beer that lacks fusel alcohols while still maintaining the complex flavor profile of the rest of the beer. Because fusel alcohols are "key contributors to the intoxicating effect [of alcohol products]," this request is very common in the brewing community (Xie 2018). By removing these fusel alcohols, the Brewmaster will have a product that he feels will be more enjoyable for his consumers to drink. During the fermentation process, fusel alcohols are produced through a process called the Ehrlich pathway, which is normally responsible for the catabolism of amino acids. There is a key divergence point within the Ehrlich pathway that is especially relevant to brewers during which the fusel aldehyde is either oxidized into a fusel alcohol or reduced into a fusel acid (Hazelwood, 2008). Using molecular genetics to disrupt key genes in this pathway, I eliminated relevant proteins, including ADH1, ADH2, ADH3, ADH4, ADH6, and AAD4 in this process to force reduction as opposed to oxidation, and thereby decrease the production of fusel alcohols. Two strains, S11-DeltaAAD4 and S11-DeltaADH4 produced fewer in fusel alcohols, a 104% and 87% decrease respectively. The Southside region of Virginia in which the brewery is located is one of the most historically disenfranchised regions of the state, and by generating a strain of yeast that better satisfies the needs of local businesses, my lab was able to make a tangible impact in the support of the long-term high-paying jobs generated by local businesses such as Three Roads Brewing Company.

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McGee TJ, Wolyniak MJ

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