the dismutation of pyruvic acid in other small organic molecules (ethanol + co, or lactate and acetate, depending on the environmental conditions) is also an important step in fermentation reactions. fermentation reactions can also be considered as disproportionation or dismutation biochemical reactions. indeed, the donor and acceptor of electrons in the redox reactions supplying the chemical energy in these complex biochemical systems are the same organic molecules simultaneously acting as reductant or oxidant.