What is the final electron acceptor in the ETS during fermentation?

What is the final electron acceptor in the ETS (electron transport system) during fermentation?

The question is incorrect. During fermentation, the Krebs cycle not progressing and NAD + is replenished by the production of ethanol or lactate (formed from pyruvate as an electron acceptor) to maintain the glycolysis. Therefore, electron transport chain is not actually running when fermentation is carried out. Transport chain electron acceptor of electrons terminal can a number of molecules, but most often, is molecular oxygen. Some bacteria use other inorganic molecules.