Understanding Bacteria Oxidizing Ethyl Alcohol to Acetic Acid

The question asks us to identify the bacterial genus responsible for converting ethyl alcohol (ethanol) into acetic acid. This process is a common cause of spoilage in alcoholic beverages like wine and beer, often referred to as 'sour rot' or 'vinegar souring'. The conversion involves the oxidation of ethanol, a key step in the production of vinegar.

Role of Acetobacter in Acetic Acid Fermentation

The genus Acetobacter specifically contains species known for their ability to perform this oxidation. These bacteria are aerobic (require oxygen) and utilize ethanol as a substrate. The overall biochemical reaction can be represented as:

$C_2H_5OH$ (Ethanol) $+ O_2 \rightarrow CH_3COOH$ (Acetic Acid) $+ H_2O$ (Water)

This transformation leads to a decrease in alcohol content and an increase in acidity due to the production of acetic acid, which imparts a sour taste and smell, thus spoiling the beverage.

Analysis of Bacterial Genera Options

Let's look at the provided options:

• Aeromonas: This genus includes facultative anaerobes that are often associated with waterborne infections and spoilage of fish and meat, but they are not primarily known for oxidizing ethanol to acetic acid.
• Acetobacter: This genus is the correct classification for bacteria that efficiently oxidize ethanol to acetic acid. They are crucial in vinegar production but detrimental when they contaminate other alcoholic drinks.
• Arthrobacter: These are common soil bacteria, generally known for their resistance to desiccation and various metabolic capabilities, but not specifically for the ethanol-to-acetic acid conversion relevant here.
• Campylobacter: This genus consists of Gram-negative bacteria commonly associated with gastrointestinal diseases in humans and animals; they do not play a role in acetic acid fermentation from ethanol.

Therefore, based on their well-established metabolic function, bacteria causing the spoilage of alcoholic beverages by oxidizing ethyl alcohol to acetic acid belong to the Genus Acetobacter.