Microbial Fermentation

Fermentation is a metabolic process that enables microbes to break down sugar and generate energy without relying on oxygen or an electron transport chain.

In fermentative organisms, pyruvate or its derivatives serve as electron acceptors, facilitating NADH oxidation to regenerate NAD⁺, essential for sustaining glycolysis.

Homolactic fermenters such as Lactobacillus and Streptococcus convert pyruvate directly into lactate without producing carbon dioxide.

This process is commonly used in the production of yogurt, sauerkraut, and pickles.

Heterolactic fermenters, such as Leuconostoc, produce lactate along with ethanol and carbon dioxide.

Alcoholic fermentation, primarily carried out by the yeast Saccharomyces, converts pyruvate into ethanol and carbon dioxide.

The end products of alcoholic fermentation are crucial in brewing, winemaking, and baking industries.

Mixed acid fermentation, common in members of the Enterobacteriaceae family, generates various end products, such as lactic acid, acetic acid, formic acid, and ethanol.