NOVELTY - The self-contained, energy self-sufficient, carbon-negative and automated system for producing biofuel e.g. biodiesel, comprises a digestion chamber comprising a first micro-organism and a substrate such as an effluent, a fluid and nutrients, and a bioreactor (1) for producing a biomass. The bioreactor comprises a vessel comprising a second micro-organism, a fluid, and nutrients, and fatty acid-containing substances. The bioreactor is functionally connected to a biodiesel reaction chamber. The biodiesel reaction chamber produces glycerol and biofuel.    USE - The system is useful: for producing biofuel such as biodiesel, ethanol, methanol, methane, paraffin-oil, hydrogen gas and other carbonaceous fuels; and in a tile-shaped modular system that is placed upon a surface of a building structure, a watercraft, an aircraft and a motor vehicle (all claimed).    ADVANTAGE - The system is self-contained, energy self-sufficient and carbon-negative and capable of automatically producing the biofuel, and can be containerized, transported and easily set up where needed.    DETAILED DESCRIPTION - The self-contained, energy self-sufficient, carbon-negative and automated system for producing biofuel e.g. biodiesel, comprises a digestion chamber comprising a first micro-organism and a substrate such as an effluent, a fluid and nutrients, and a bioreactor (1) for producing a biomass. The bioreactor comprises a vessel comprising a second micro-organism, a fluid, and nutrients, and fatty acid-containing substances. The bioreactor is functionally connected to a biodiesel reaction chamber. The biodiesel reaction chamber produces glycerol and biofuel from a reaction between feedstock and an alcohol in the presence of a base. Glycerol is used as a source of fuel to power various aspects of the system. The net energy output is 2.5 kWh per liter of biofuel, and is 1.5 times the input energy such as kinetic energy, photon energy, or electromagnetic energy. The digestion chamber is in fluid communication with the vessel of the bioreactor. A pumping unit is arranged for communicating a gas from the digestion chamber to the vessel of the bioreactor. The proliferation of the first organism generates a gas and an alcohol, where the gas is transferred to the bioreactor. The second micro-organism in the vessel of the bioreactor utilizes the gas to synthesize a biofuel and high-protein compounds. The micro-organism has minimal bioflocculation and biochelatic properties of metal ions. INDEPENDENT CLAIMS are included for:    (1) a system for producing algal biomass; and    (2) a tile-shaped modular system.    DESCRIPTION OF DRAWING(S) - The figure shows a paired bioreactor such as symbiotic digester and photobioreactor system.    Bioreactor (1)    First outlet (2)    In-line centrifuge (3)    Second outlet (4)    Pipe (5)    Cold press. (7)