biphenyl + H(+) + NADH + O2 = (2R,3S)-3-phenylcyclohexa-3,5-diene-1,2-diol + NAD(+) Binds 1 [2Fe-2S] cluster per subunit. Binds 1 Fe cation per subunit. Xenobiotic degradation; biphenyl degradation; 2-hydroxy-2,4-pentadienoate and benzoate from biphenyl: step 1/4. Heterohexamer consisting of three BphA subunits and three BphE subunits. A ferredoxin (BphF) and a ferredoxin reductase (BphG) must be present to obtain activity (By similarity). Belongs to the bacterial ring-hydroxylating dioxygenase alpha subunit family.