Catalyzes the cleavage of beta-carotene at its central double bond (15,15') to yield two molecules of all-trans-retinal. all-trans-beta-carotene + O2 = 2 all-trans-retinal Belongs to the Brp/Blh beta-carotene diooxygenase family. Was originally thought to regulate bop expression (PubMed:6093059). However, this seems to result from a polar effect on the downstream gene bat, which forms a transcription unit with brp.