Catalyzes the double cyclization reaction which converts lycopene to beta-carotene (PubMed:2254247, PubMed:11943208, PubMed:20178989). Also catalyzes the double cyclization reaction which converts neurosporene to 7,8-dihydro-beta-carotene via monocyclic beta-zeacarotene (PubMed:8898919). May also convert zeta-carotene to bicyclic 7,8,7',8'-tetrahydro-beta-carotene (PubMed:8898919). a carotenoid psi-end group = a carotenoid beta-end derivative all-trans-lycopene = gamma-carotene gamma-carotene = all-trans-beta-carotene all-trans-neurosporene = beta-zeacarotene beta-zeacarotene = 7,8-dihydro-beta-carotene Activity is increased in the presence of NAD(P)H (PubMed:11943208, PubMed:20178989). NADPH is not involved directly in the cyclization reaction, but must play an indirect role, e.g. as an allosteric activator (PubMed:11943208). Carotenoid biosynthesis; beta-carotene biosynthesis. Membrane-bound. Belongs to the lycopene cyclase family.