The world is facing an energy crisis and environmental issues due to the depletion of fossil fuels and increasing levels of CO2 in the atmosphere. Growing algae offers one practical solution for these global issues because they capture CO2 and store it in high energy biomass compounds using photosynthesis. Their biomass contains a large percentage of oils that can be converted into biofuel. This oil producing ability of algae can be controlled to maximize biofuel production by changing their growth conditions. The purpose of this proposal is to generate new strains of microalgae capable of producing high amounts of lipids (oil) under extreme growth conditions. These conditions are needed to avoid contamination from bacteria and fungi when algae are grown in open systems for mass production.