Citizen Science Week One: Introduction to Fermentation


The topic I chose out of the coffee filter last week was FERMENTATION.

I was really excited about this topic, because the little I knew about fermentation is super interesting:

1) It’s involved in producing foods that are really good for your microbiome: sauerkraut, yogurt, kombucha, kimchi.

2) It’s involved somehow with the creation of alcoholic beverages.

Looking into fermentation, I found an Oxford dictionary definition: “the chemical breakdown of a substance by bacteria, yeasts, or other microorganisms, typically involving effervescence and the giving off of heat.” Another definition: “Fermentation is a metabolic process in which an organism converts a carbohydrate, such as starch or a sugar, into an alcohol or an acid.” The study of fermentation is called zymology, which as names go is pretty rad. It’s a natural process, meaning it can happen without any human intervention. Scientists have been studying fermentation since the 1600s.

Fermentation is an anaerobic pathway for breaking down glucose, meaning it does not require oxygen to occur. There are (at least) two separate, common kinds of fermentation: lactic acid fermentation, which generates lactic acid as a byproduct, and alcohol fermentation, which produces ethanol as a byproduct.

Lactic Acid Fermentation: C6H12O6 (glucose) → 2 CH3CHOHCOOH (lactic acid)

Ethanol Fermentation: C6H12O6 (glucose) → 2 C2H5OH (ethanol) + 2 CO2 (carbon dioxide)

The former process is what happens in yogurt and exhausted muscles, the latter involved in producing wine and beer. In alcohol fermentation, there is an upper limit to how much alcohol can be produced without being toxic to the yeast that generates it, which can range from 5-21% ethanol. Aside from producing foods and alcohol, fermentation is also involved in the creation of industrial products like biofuels and hydrogen gas.

I definitely need to brush up on my biochemistry knowledge to understand these reactions a little better. I’m really interested in learning more about using fermentation to produce biofuels.