NOVELTY - Production of biofuels from algae, involves cultivating an oil-producing algae by promoting sequential photoautotrophic and heterotrophic growth; producing oil by heterotrophic growth of algae where the heterotrophic algae growth is achieved by introducing a sugar feed to the oil-producing algae; extracting an algal oil from the oil-producing algae; and converting the algal oil to form biodiesel.    USE - For producing biofuels e.g. biodiesel product, which is fatty acid ethyl ester or an alkane (claimed), bioethanol.    ADVANTAGE - The biodiesel product is free of sulfur. The process is highly efficient and energy-positive, i.e. the energy produced in the form of fuels is far in excess of external input energy, because very little fossil energy is used. Algae growth requires none of the heavy machinery, expensive fuels, or chemical fertilizers and pesticides required by conventional agriculture. Further, the algae can be processed near the growth ponds, eliminating transportation costs. The algal oil contains little or no sulfur, so production of biodiesel using the process reduces sulfur emissions, even compared to ultra low sulfur petroleum diesel. Because of better combustion efficiency, biodiesel produces about 20% less carbon monoxide upon use by a consumer and burns more efficiently which results in a smoother-running engine. The equivalent cetane number of biodiesel is higher than petroleum diesel, reducing diesel noise and knock. Biodiesel produces less soot, reducing particulate emissions by up to 75% and nearly eliminating the black smoke often associated with diesel engine exhausts. Biodiesel also has a higher flash point near 150 degrees C compared to petroleum diesel at 70 degrees C, so it is safer to store and handle. Biodiesel breaks down about four times faster in the environment, so spills are less enduring. Biodiesel has higher lubricity so fuel injection systems and other engine components can have a longer life. Further, biodiesel can be mixed with petroleum diesels during the transition to 100% biodiesel fuels. Conventional diesel engines do not need to be modified to use biodiesel. The smell of biodiesel fuel and biodiesel exhaust is cleaner and lacks most of the familiar diesel aroma.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a system (10, 20) for production of biodiesel (58) from algae comprising: a feed biomass source (12) operatively connected to a depolymerizing reactor (32) configured for forming a sugar feed from the feed biomass source, where the feed biomass source includes algal biomass (22); algae growth reservoirs including a carbon dioxide source (4, 28) and a mixing mechanism configured to circulate an oil-producing algae within the algae growth reservoirs, where the algae growth reservoirs include an algae growth control unit for achieving both autotrophic growth and heterotrophic growth; a sugar separator (34) operatively connected to the depolymerizing reactor and the algae growth reservoirs, the sugar separator configured for directing at least a portion of the sugar feed to the algae growth reservoirs; an oil extraction bioreactor (14) operatively connected to the algae growth reservoirs and configured for biologically rupturing algae cells and/or algal oil vesicles of the oil-producing algae to form an algal oil (18) and algal residue; and a conversion reactor (16) operatively connected to the oil extraction bioreactor to convert at least a portion of the algal oil to biodiesel.    DESCRIPTION OF DRAWING(S) - The figure shows a process flow diagram of a system for the production of biofuels from algae.    System (10, 20)    Feed biomass source (12)    Bioreactor (14)    Conversion reactor (16)    Algal oil (18)    Depolymerizing reactor (32)    Sugar separator (34)    Carbon dioxide source (4, 28)    Biodiesel. (58)