Contamination by Brettanomyces is a major contributor to spoilage of finished wine. One mechanism of spoilage is through metabolism of grape-derived hydroxycinnamic acids (HCAs). Brettanomyces yeast convert these compounds into volatile products responsible for off-aromas and flavors. Phenolic acid decarboxylase (PAD) is the first enzyme in the metabolic pathway. This project will characterize the role of Brettanomyces metabolism on wine aroma and flavor through molecular analysis of the PAD enzyme. We will clone and characterize the PAD enzyme gene and protein, and also determine the extent of gene sequence variation from different Brettanomyces isolates.A better understanding of the spoilage process is essential to reducing the risk associated with these microorganisms and developing new tools to address the economic losses they cause.