Which microbes benefit from oxygen in wine?

• A. Acetobacter, Brettanomyces
• B. Saccharomyces cerevisiae
• C. Lactobacillus
• D. Pediococcus

Answer: (A)

Oxygen availability shapes which microbes can thrive in wine. Some organisms specifically benefit from the presence of oxygen because it enables their metabolism to proceed in ways that affect flavor and stability.

Acetobacter uses oxygen to oxidize ethanol into acetic acid, turning wine into vinegar if oxygen exposure is sustained. This is a direct, oxygen-dependent spoilage pathway, so they thrive when oxygen is present.

Brettanomyces is a yeast that can grow better in oxygen-rich or micro-oxygenated environments and is well known for producing distinctive spoilage aromas like phenolics. Oxygen helps its metabolism and growth, increasing its impact on wine.

Saccharomyces cerevisiae, while capable of tolerating oxygen and using it during the early growth phase, is primarily the fermenter that converts sugars to alcohol under low-oxygen conditions; its relationship to oxygen isn’t about benefiting from it in the same way as the two other microbes. Lactobacillus and Pediococcus can function across a range of oxygen levels, but they aren’t characterized as benefiting from oxygen in the same direct, spoilage-facilitating way as Acetobacter and Brettanomyces.