Part of the electron transfer component of biphenyl dioxygenase, transfers electrons from ferredoxin (BphF) to NADH. H(+) + NAD(+) + 2 reduced [2Fe-2S]-[ferredoxin] = NADH + 2 oxidized [2Fe-2S]-[ferredoxin] Xenobiotic degradation; biphenyl degradation. This dioxygenase system consists of four proteins: the two subunits of the hydroxylase component (BphA and BphE), a ferredoxin (BphF) and a ferredoxin reductase (BphG). Belongs to the bacterial ring-hydroxylating dioxygenase ferredoxin reductase family.