The Role of Enzymes in Alcohol Distillation

Production of fermented alcoholic beverages from starch-based raw materials has been practiced for centuries. Materials commonly used include corn and rye for bourbon production; wheat/barley blends for grain spirits production; as well as potatoes (potato vodka).

Starch-based fermentation uses enzymes to break glucose chains down into shorter molecules that yeast can use to convert into alcohol. A complex enzyme system called alcohol dehydrogenase (ADH), Cytochrome P450 Isozymes such as Cyp2E1, and Catalase help create the necessary oxidative pathways of alcohol metabolism.

At the center of alcoholic fermentation lies ADH in the yeast cell cytosol, where it converts alcohol to acetaldehyde and transfers two electrons to NADPH oxidase for further reduction, producing hydrogen peroxide which is eventually transformed back to ADH by catalase in another reaction.

However, this oxidative reaction is limited by oxygen availability and demand in cells; with alcohol consumption creating high demand and insufficient supply. Oxidation becomes inefficient and produces harmful reactive oxygen species (ROS), including superoxide which damage cells.

Oxidative reactions rely heavily on hydrogen peroxide production by mitochondria, in part by another isozyme of Cytochrome P450 called xanthine Oxidase. Chronic alcohol consumption increases H2O2 production in liver hepatocytes via chronic alcohol intake; this allows more efficient ethanol oxidation via Cytochrome P450 2E1 isozymes, leading to more ROS production.