2016 AIChE Annual Meeting
Engineering Medium Chain Volatile Ester Biosynthesis By Eeb1 in S. Cerevisiae
Fatty acid ethyl esters are organic compounds produced during microbial fermentation and fruit ripening as secondary metabolites. These compounds have a wide variety of application in the food, cosmetic and biofuel industries. In particular, short and medium chain esters such as isoamyl acetate (a banana flavored fruit additive) and ethyl acetate (an industrial solvent) are naturally produced in the yeast saccharomyces cerevisiae (S. cerevisiae). The biosynthetic pathways that produces these esters involves a condensation reaction between an alcohol and an acyl- or acetyl-CoA by alcohol-O-acetyltransferases (AATase, E.C. 2.3.1.84 and 2.3.1.74). Previous high throughput screening of cell lysates revealed that Eeb1 exhibits high activity towards ethyl esters with acyl-CoAs of carbon chain lengths from C4-C12. However, the understanding of biosynthesis of medium fatty chain ethyl esters in yeast is not completely understood. Through overexpression studies, it has been revealed that Eeb1 localizes to the mitochondria, while mutations on the N terminus results in localization to lipid droplets. The mutations also increase the enzymatic activity of Eeb1 by 2.7-fold. This study presents the results of localization, studies activity assays, and western blot analysis to determine the relationship between localization, activity, and expression of Eeb1; which will help to further understand the biosynthesis of fatty acid ethyl esters in yeast. Future research will focus on the development of a biosynthetic pathway to efficiently produce octanoyl-CoA in cytosol and subsequently produce a high yield of octanoyl acetate under conditions of fermentation.