1. Substrate: Lactobacillus acidophilus primarily uses sugars (like lactose, glucose, and galactose) as its energy source.
2. Glycolysis: The sugar molecule is broken down into pyruvate through a series of enzymatic reactions in the glycolysis pathway. This process generates a small amount of ATP (adenosine triphosphate), the cell's energy currency.
3. Lactic acid fermentation: Since Lactobacillus acidophilus lacks the ability to use the electron transport chain (the process used by many organisms to generate more ATP from pyruvate), it relies on fermentation. In this process, pyruvate is converted into lactic acid, regenerating NAD+ (nicotinamide adenine dinucleotide), a crucial molecule for glycolysis to continue.
In summary, Lactobacillus acidophilus uses sugars as fuel, breaks them down through glycolysis, and then converts the resulting pyruvate into lactic acid to generate energy and recycle essential molecules for continued sugar breakdown.
This process is also responsible for the characteristic sour taste of fermented products like yogurt, as lactic acid is a byproduct.
