Date of Award

January 2021

Degree Type

Open Access Thesis

Document Type

Master Thesis

Degree Name

Master of Science (MS)



First Advisor

Patrick J. Calie

Department Affiliation

Biological Sciences

Second Advisor

Christian M. Paumi

Department Affiliation

Biological Sciences

Third Advisor

David M. Hayes

Department Affiliation

Biological Sciences


The Glutathione pathway, (GSH) is an antioxidant system in yeast that increases cell viability and contributes to the production of desirable beer flavors during industrial fermentation. Despite its importance, studies using the GSH pathway: GSH1, GSH2, GLR1, and SOD1 genes, to trace the evolutionary history of beer strains are lacking. As a result, the investigator sought to elucidate the phylogenetic relationships between four commonly used industrial beer strains: California Ale, London Ale, Oktoberfest, and Brettanomyces bruxellensis through single-gene sequencing analysis of the GSH pathway. It was hypothesized that the actions of these GSH genes are unique and potentially upregulated in beer brewing yeasts when compared to non-brewing yeasts strains. In order to assess this theory, GSH pathway genes from the experimental industrial strains, were sequenced in order to demonstrate that brewing yeast exhibit identical GSH pathway sequences as an adaptation to their shared brewing environments.

Following genome sequencing and phylogenetic analyses, the investigator found that these strains possessed identical GSH pathways as a result of various physiological adaptations and prolonged use within industrial settings. The investigator’s results highlight the evolutionary significance and functionality of GSH pathway genes and demonstrate the essentialness of antioxidant activity in industrial yeast strains. These results also revealed that important strain related associations can be inferred through an analysis of essential metabolic pathways.

Included in

Biochemistry Commons