Biochemistry | Alcoholic Fermentation

Alcoholic Fermentation Process
🔬 Alcoholic fermentation is a biochemical process converting pyruvate into ethanol and carbon dioxide ($\text{CO}_2$).
🍞 The released $\text{CO}_2$ is responsible for making yeast-leavened bread spongy.
🔗 This pathway is initiated by the production of pyruvate, primarily obtained as the final product of Glycolysis.

Metabolic Steps and Yield
🧬 Glycolysis converts one glucose molecule into two pyruvate molecules, two $\text{NADH}$, and two $\text{ATP}$.
1️⃣ The first enzymatic step involves pyruvate decarboxylase, which releases $\text{CO}_2$, changing the three-carbon pyruvate into the two-carbon intermediate acetaldehyde.
2️⃣ Acetaldehyde is converted to ethanol by the enzyme alcohol dehydrogenase, which simultaneously regenerates $\text{NADH}$ to $\text{NAD}^{+}$, ensuring Glycolysis can continue.
💰 The net gain from glucose fermentation is two molecules of ethanol and two $\text{ATP}$.

Key Points & Insights
➡️ The regeneration of $\text{NAD}^{+}$ from $\text{NADH}$ during ethanol formation is crucial for maintaining the continuation of the preceding Glycolysis pathway.
➡️ Saccharomyces cerevisiae (yeast) utilizes this specific metabolic route, which is vital for the production of alcoholic beverages in the food industry.
➡️ The entire process yields a net energy gain of only two $\text{ATP}$ molecules per molecule of glucose processed.

📸 Video summarized with SummaryTube.com on Mar 04, 2026, 17:51 UTC