Saponification is the chemical reaction responsible for the protocell behavior we have observed under the microscope with Martin, and also produces soap when done at larger scales. So saponification rocks!

  • Definition

Saponification is the reaction between lye (HO-) and an ester (which is our case is animal or vegetal fat/oil). The reaction produces alcohol and soap (carboxylate ions mixture).


Note: the R in organic chemistry states for a hydrocarbon chain. This is a general formula that works for any kind of R and R’ chain.

This is the general definition of the reaction. As you can see in the formula what is happening is basically that the hydrocarbon chain R’ of the ester detaches and binds to the HO-, forming an alcohol.

  • Saponification using animal/vegetal fat/oil

Here I’ll explain why the reaction works with animal fat and vegetal oils.

Fat and oils are produced in the organisms from fatty acids (main kind of lipids present in living organisms).


Fatty acids are important components of plants, animals and other microorganisms and have many biological functions.

One of the main functions is however energy storage that the cell/organism can use later when needed.

In order to store these fatty acids, the cells (animal and plants) produce molecules called triglycerides = they’re simply a ‘package’ of 3 fatty acids molecules.



Cells have enzymes that are able to perform this reaction using 3 fatty acids and glycerol inside. And…. triglycerides are tri-ESTERS (ester groups are in blue in the image above).

When triglycerides in fat/oil react with aqueous NaOH or KOH, they are converted into soap (carboxylate salts) and glycerol.


Check this for info about saponification, lipids, fatty acids and oils/fat: