Oxidative decarboxylation reactions are oxidation reactions in which a carboxylate group is removed, forming carbon dioxide. They often occur in biological systems: there are many examples in the citric acid cycle.
In this process, one pyruvic acid molecule is used to form one NADH and 2 ATP, catalyst by the pyruvate dehydrogenase complex enzyme.
Pyruvic acid + NAD + coenzyme A + water --> acetyl coenzyme A + NADH + H+ + CO2
The transformation of glyoxylate to methanoic acid is also an oxidative decarboxylation.