Characterization of <i>Brettanomyces bruxellensis</i> Phenolic Acid Decarboxylase Enzyme Expressed in <i>Escherichia coli</i>

Brettanomyces yeasts are considered spoilage organisms in commercial fermentation settings; however, some historical beer styles and several modern specialty beer styles rely on Brettanomyces for unique aroma and flavor contributions. The organoleptic properties of beer utilizing intentional Brettanomyces fermentations can be unpredictable and inconsistent. This study investigates the contributions of Brettanomyces fermentations to volatile phenolic character by expression of phenolic acid decarboxylase enzyme cloned from B. bruxellensis. Protein was expressed and isolated from Escherichia cells. The enzyme has broad temperature and pH ranges, and showed variable activity against the most common potential hydroxycinnamic acid substrates.