Microbiology Practice Exam

What are the byproducts of homolactic fermentation?

1. Water and carbon dioxide

2. Glucose and oxygen

3. Lactic acid

4. Ethanol and acetic acid

The correct answer is: Lactic acid

Homolactic fermentation is a metabolic process performed primarily by certain bacteria, such as Lactobacillus, and some fungi. During this process, glucose is broken down anaerobically (without oxygen) to produce lactic acid as the main byproduct. In this pathway, one molecule of glucose is converted into two molecules of lactic acid through glycolysis and subsequent steps specific to lactic acid fermentation. The process does not produce carbon dioxide or ethanol, which are byproducts seen in other types of fermentation. Therefore, the production of lactic acid is the defining feature of homolactic fermentation, making it the correct answer. The simplicity of this pathway is significant as lactic acid can be further utilized in various applications, such as in food preservation and production of certain fermented foods.