NOVELTY - A closed system bioreactor apparatus comprises flexible tube(s), peristaltic roller(s), and a thermal barrier, where the flexible tube(s) is capable of containing an aqueous medium, the peristaltic roller(s) is operably coupled to the tubes to circulate the medium through the tubes and to remove gas bubbles from the tubes, the thermal barrier is within the tube(s) to regulate the temperature of the medium, and the medium may be alternatively directed above or below the barrier to thermally isolate or thermally expose the medium to the environment.    USE - The apparatus is useful for biodiesel producing system for producing biodiesel from algae. The apparatus can also be used for producing products, e.g. methane, animal or human food, substrates for polymer synthesis, or other chemical products. The apparatus can be used for culturing organisms that rely in whole or in part on exposure to sunlight, e.g. photosynthesis algae.    ADVANTAGE - The apparatus provides competitively priced, biologically closed system with better control of predators, competing species, temperature, and other environmental factors than the open pond model, reduces the problems from competing organism, predatory organism, pathogenic organisms and/or other extraneous species. The apparatus provides improve thermal regulation to maintain temperature in range compatible with optimal productivity of aquatic organisms, scalable to any level of production desired from small backyard operation to one covering square miles of surface.    DETAILED DESCRIPTION - The apparatus includes multiple axial vortex inducers, two control housings, aquatic organism(s) in the medium, whiff pool device, sipper tube(s), and gas bubbler. During daylight hours the flow of the aqueous medium is directed below the thermal barrier to maintain the temperature of the suspension at ground temperature or above the thermal barrier to warm the suspension. During nighttime hours the flow of the aqueous medium is directed above the thermal barrier to cool the suspension and below the thermal barrier to maintain the temperature of the medium at ground temperature. The outer polyethylene surface of the tubes is 0.01 inch thick. The thermal barrier is made of 1.0 inch thick polyethylene foam. The upper surface of the thermal barrier comprises a layer of sand, a translucent ceramic or plastic, a silicate or glass. The upper surface of the thermal barrier exhibits an infrared emissivity of close to 1.0. The upper surface of the tubes is indented with a linear Frenel pattern that collects sunlight from a lower Snell's law angle and directs it into the aquatic organisms in the medium. The tubes are layed out perpendicular to the low angle southern sun for the winter months in temperate climates. The gas bubbler comprises a perforated neoprene membrane through which gas is bubbled. An INDEPENDENT CLAIM is also included for biodiesel producing system for producing biodiesel from algae.    DESCRIPTION OF DRAWING(S) - The figure shows schematic example of biodiesel producing system.