Involved in the biosynthesis of C(50) beta-cyclic carotenoids (PubMed:17008032). The elongase/hydratase domain 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 (By similarity). 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). The beta-cyclase domain may produce the C(50) beta-cyclic carotenoid C.p.450 from the C(50) carotenoid dihydrobisanhydrobacterioruberin (DH-BABR) (Probable). all-trans-lycopene + dimethylallyl diphosphate + H2O = dihydroisopentenyldehydrorhodopin + diphosphate dimethylallyl diphosphate + H2O + isopentenyldehydrorhodopin = dihydrobisanhydrobacterioruberin + diphosphate Carotenoid biosynthesis. May form a complex with LbtA. Belongs to the UbiA prenyltransferase family.