This is known as lactic acid fermentation. So let's focus on ethanol fermentation. So basically, yeast cells and several other bacterial cells utilize this process of fermentation. So alcoholic fermentation to basically reform those NAD plus coenzyme molecules. And what happens is the pyruvate molecules ultimately are transformed into the ethanol molecule of this process actually takes place in two steps. The first step is a decarboxylation process and the enzyme that catalyzes this process is known as pyruvate decarboxylase.