NOVELTY - A bioreactor, for cultivating photosynthetic organisms, comprising a first lighting system received in the isolated space of the container, the first lighting system comprising one or more light-emitting substrates each having a first surface and a second surface opposite to the first surface, the one or more light-emitting substrates configured to supply a first amount of light from the first surface and a second amount of light from the second surface to at least some of photosynthetic organisms retained in the isolated space, is new.    USE - The bioreactor, system, and method are useful for cultivating photosynthetic organisms. The bio-system is useful for producing biofuel from algae.    ADVANTAGE - The present invention provides approaches for supplying light to a bioreactor and for sustaining the photosynthetic processes of a biomass cultivated within a reactor.    DETAILED DESCRIPTION - A bioreactor, for cultivating photosynthetic organisms, comprises (i) a container having an exterior surface and an interior surface, the interior surface defining an isolated space configured to retain photosynthetic organisms and cultivation media; and (ii) a first lighting system received in the isolated space of the container, the first lighting system comprising one or more light-emitting substrates each having a first surface and a second surface opposite to the first surface, the one or more light-emitting substrates configured to supply a first amount of light from the first surface and a second amount of light from the second surface to at least some of photosynthetic organisms retained in the isolated space. INDEPENDENT CLAIMS are:    (1) a method for providing light energy to a substantial portion of photosynthetic organisms in liquid growth media within a bioreactor;    (2) a photosynthetic biomass cultivation system comprising (i) a controller configured to automatically control at least one process variable associated with cultivating a photosynthetic biomass, and (ii) a bioreactor comprising a structure having an exterior surface and an interior surface, the interior surface defining an isolated space configured to retain the photosynthetic biomass suspended in cultivation media, and a lighting system received in the isolated space of the structure, the lighting system comprising one or more light-emitting elements including a light-emitting area, the light-emitting area forming part of a light- emitting-area to reactor-volume interface;    (3) a method for increasing a ratio of light-emitting-area to a photobioreactor-volume interface of a photobioreactor;    (4) a bio-system, for producing biofuel from algae, comprising (i) a bioreactor having a lighting system arranged to direct an amount of light on at least some algae located within the bioreactor, the algae and lighting system respectively oriented within the bioreactor to increase a photosynthetic process of the algae, (ii) a control system coupled to the bioreactor to monitor and/or control at least one environmental condition within the bioreactor, and (iii) a light source optically coupled to the lighting system; and    (5) a method of cultivating algae in a bioreactor.    DESCRIPTION OF DRAWING(S) - The figure is a bioreactor which comprises    container; (24)    exterior surface; (26)    lighting system; (32)    light-emitting substrates; and (34)    inlet and/or outlet conduits . (40, 42, 44)