Abstract: Biosecure algae and methods for preparing biosecure algae that have a substantially decreased capability to survive in a natural environment are described. The methods include transforming a genetically modified alga to include an essential gene that is operably linked to a promoter system that is active only in the presence of an inducer compound, transforming the genetically modified alga to include a lethal gene that is operably linked with a promoter system that is inactive only in the presence of a repressor compound. The biosecure algae are only able to survive in an artificial algae culture that includes factors or conditions not found in a natural environment.

Abstract: Recombinant oleaginous alga that include one or more heterologous genes that increase the ability of the alga to use one or more natural saccharides such as cellulosic or hemicellulosic sugars for algal growth are described. The recombinant oleaginous algae are transformed to include one or more genes expressing sugar metabolizing enzymes or sugar transporting proteins, along with suitable control elements. Use of natural saccharides as a carbon source can allow the algae to produce biofuel precursors in a relatively efficient manner. Processes for preparing the alga, growing the alga, and extracting the biofuel precursors from the alga are also described.