TECHNOLOGY FOCUS - BIOLOGY - Preferred Process: The convertion of the algal oil to form biodiesel is by direct hydrogenation or transesterification of the algal oil. The process further involves introducing a nitrogen-fixing algae to the oil-producing algae to provide nitrogen as a nutrient, or using the nitrogen-fixing algae as the oil-producing algae. The nitrogen-fixing algae consists of blue-green algae or cyanobacteria. The sugar feed is the primary source of both carbon and energy in the heterotrophic growth stage. The autotrophic growth includes enriched carbon dioxide. The sugar feed is provided by cultivating algae and extracting the sugar feed from it. The heterotrophic growth stage is initiated using a stress induction mechanism. The stress induction mechanism includes at least one of light deprivation, nutrient deprivation, injection of a reactive oxygen source, or chemical additives. Preferred Components: The oil-producing algae includes a member selected from diatoms (bacillariophytes), green algae (chlorophytes), blue-green algae (cyanophytes), golden-brown algae (chrysophytes) and/or haptophytes (preferably Amphipleura, Amphora, Chaetoceros, Cyclotella, Cymbella, Fragilaria, Hantzschia, Navicula, Nitzschia, Phaeodactylum, Thalassiosira, Ankistrodesmus, Botryococcus, Chlorella, Chlorococcum, Dunaliella, Monoraphidium, Oocystis, Scenedesmus, Tetraselmis, Oscillatoria, Synechococcus and/or Boekelovia, particularly Chlorella and/or Dunaliella). Preferred Device: The conversion reactor is configured for conversion accomplished by direct hydrogenation of the algal oil or by transesterfication of the algal oil to produce biodiesel. The algae growth control unit includes a lipid trigger to simultaneously accelerate oil production during autotrophic growth, a sugar feed to accelerate heterotrophic growth, and a stress induction mechanism for controlling available light and nutrient levels to the algae growth reservoir. The algae growth control unit includes separate autotrophic growth reservoirs and heterotrophic growth reservoirs within the algae growth reservoirs which are operatively connected to one another and configured for autotrophic growth and heterotrophic growth respectively. EXAMPLE - No suitable example given.