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A reaction between fusel alcohols and Acetyl-CoA and Acyl CoA in Saccharomyces cervisiae uses ester synthase enzymes, such as alcohol acetyltransferase (AATase), to produce esters. Fusel alcohols are a mixture of many alcohols that are produced during fermentation. Both the type of fusel alcohol and strain of yeast factor into which esters will be produced during fermentation. Esters are essential to the final flavor determination of the beer and with many factors affecting their production, problems can occur in a hurry. Low ester production could cause a poor flavor profile and cost brewers money and time if the beer is unusable and cannot be sold. This research has been dor:e in an attempt to compare yeast strains with similar types of produced esters, resulting in similar flavor profiles, and then factor in other characteristics such as price. This will allow the determination of which yeast, or combination of yeasts, would be most cost effective, resistant to diseases or temperature changes, and still give the same flavor profile. Several experimental setups were constructed in attempt to efficiently produce and characterize esters. S. cerevisiae was incubated with a fusel alcohol in aerobic conditions for 12-24 hours. The alcohols and esters were then extracted with pentane for gas chromatography mass spectroscopy (GC-MS) analysis. Data analysis has shown that we cannot jump into the pathway at this point, but instead must back up and try to influence fusel alcohol production at earlier points in the pathway. Most samples have shown little to no esters that can clearly be identified from their precursor alcohol. Research is currently being done, and will continue in the future, in order to find the best experimental method for ester production. Once that is accomplished, different strains of yeast will be tested to see what esters are produced by the different strains.

Content Notes

Final Report Form, Abstract, Presentation

First Advisor

Francis Mann



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