Answer: Fermentation
In the process of fermentation the 2 pyruvate molecules are converted into two carbon dioxide molecules. In the process of two NADPH molecules are converted into two NAD+ molecules. These NADPH are the result of breakdown of a glucose molecule(glycolysis) which includes release of two ATPs.
There are three fate of pyruvate molecule that is a product of glycolysis reaction.
1- aerobic( krebs cycle)
2-anaerobic microbes( fermentation)
3- anaerobic vertebrates ( lactate formation)
The conversion of pyruvate molecules in to two carbon dioxide is anaerobic process( occurs in microorganisms).