an aldehyde + H2O + 2 oxidized [2Fe-2S]-[ferredoxin] = a carboxylate + 3 H(+) + 2 reduced [2Fe-2S]-[ferredoxin] Binds 1 [4Fe-4S] cluster per subunit. Binds 1 W-bis(molybdopterin guanine dinucleotide) (W-bis-MGD) cofactor per subunit. Homodimer. Belongs to the AOR/FOR family.