O. oeni is the bacterium responsible for malolactic acid fermentation or deacidification following fermentation of most red wines and some white and sparkling wines. In order to better understand the microbe’s metabolic pathways, the researchers standardized a method to extract proteins from O. oeni and characterized its membrane and cytosolic proteome. They identified 152 unique proteins, which was probably about 10 percent of the total proteome. The investigators found enzymes involved in metabolic pathways that can lead to changes in levels of nutty and buttery flavors in wine.