Involved in the biosynthesis of the acyclic C50 carotenoid bacterioruberin (BR) (PubMed:21840984). Acts as a bifunctional elongase/hydratase that catalyzes the elongation of lycopene by attaching a C(5) isoprene unit at C-2, as well as the hydroxylation of the previous end of the molecule (PubMed:21840984). The enzyme acts at both ends of the substrate, and catalyzes the conversion of lycopene to the C(45) intermediate dihydroisopentenyldehydrorhodopin (DH-IDR) and the conversion of isopentenyldehydrorhodopin (IDR) to the C(50) carotenoid dihydrobisanhydrobacterioruberin (DH-BABR) (By similarity). Can also catalyze the conversion of lycopene to tetrahydrobisanhydrobacterioruberin (TH-BABR) (PubMed:21840984). all-trans-lycopene + dimethylallyl diphosphate + H2O = dihydroisopentenyldehydrorhodopin + diphosphate dimethylallyl diphosphate + H2O + isopentenyldehydrorhodopin = dihydrobisanhydrobacterioruberin + diphosphate Inhibited by bacterioopsin. Carotenoid biosynthesis. Loss of bacterioruberins production. Belongs to the UbiA prenyltransferase family.