Cellular respiration, like burning, results in the complete oxidation of glucose into CO2 and water. Fermentation, on the other hand, does not fully oxidize glucose. Instead, small, reduced organic molecules are produced as waste. As a result, cellular respiration releases more energy from glucose than fermentation.

Anaerobic respiration is a type of respiration where oxygen is not used; instead, organic or inorganic molecules are used as final electron acceptors. Fermentation includes processes that use an organic molecule to regenerate NAD+ from NADH.

The main difference between fermentation and respiration is that during fermentation, NADH is not used in the oxidative phosphorylation in order to generate ATP whereas, during respiration, NADH is used in the oxidative phosphorylation in order to generate three ATPs per NADH.

Fermentation is similar to anaerobic respiration—the kind that takes place when there isn’t enough oxygen present. However, fermentation leads to the production of different organic molecules like lactic acid, which also leads to ATP, unlike respiration, which uses pyruvic acid.

There are two types of fermentation, alcoholic fermentation and lactic acid fermentation.

Glycolysis — the metabolic pathway that converts glucose (a type of sugar) into pyruvate — is the first major step of fermentation or respiration in cells.

The overall chemical formula for ethanol fermentation is: C6H12O6 (glucose) → 2 C2H5OH (ethanol) + 2 CO2 (carbon dioxide) + energy. Because there are two pyruvates produced per one glucose molecule, there are two ethanol molecules and two carbon dioxide molecules produced after fermentation.

Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen.

The purpose of fermentation in yeast is the same as that in muscle and bacteria, to replenish the supply of NAD+ for glycolysis, but this process occurs in two steps: Alcoholic fermentation consists of pyruvate being first converted into acetaldehyde by the enzyme pyruvate decarboxylase and releasing CO2.

Fermentation reactions occur in the cytoplasm of both prokaryotic and eukaryotic cells. In the absence of oxygen, pyruvate does not enter the mitochondria in eukaryotic cells.

Humans cannot ferment alcohol in their own bodies, we lack the genetic information to do so. These biochemical pathways, with their myriad reactions catalyzed by reaction-specific enzymes all under genetic control, are extremely complex. We will only skim the surface at this time and in this course.

This crazy, live process is fermentation. But there are other types of fermented drinks, too, and they’re not all alcoholic. Fermentation basically happens when micro-organisms convert carbs or sugars into either alcohol or acid. Yeast creates alcohol – as with beer, wine and cider – while bacteria creates lactic acid.

The process of fermentation in winemaking turns grape juice into an alcoholic beverage. During fermentation, yeasts transform sugars present in the juice into ethanol and carbon dioxide (as a by-product).

A lot of alcoholic beverages are coming on to the market using “cold-brewed sugar” or “fermented cane sugar” as their alcohol base. Commonly referred to in the industry as “sugar-brews,” this type of a base is produced by fermenting sugar from cane, beet, or corn.

Yeasts are responsible for this process, and oxygen is not necessary, which means that alcoholic fermentation is an anaerobic process. Byproducts of the fermentation process include heat, carbon dioxide, water and alcohol.