Algae Lipids Protein Carbohydrate Anabaena cylindrica 4–7 43–56 25–30 Aphanizomenon flos-aquae Arthrospira maxima 6–7 60–71 13–16 Botryococcus braunii Chlamydomonas rheinhardii Chlorella ellipsoidea Chlorella pyrenoidosa Chlorella vulgaris 4–22 51–58 12–17 Dunaliella salina In the future of renewable energy, algae has the potential to become a significant source of biofuels. Either by directly generating ethanol or producing feedstocks of oil for biodiesel, or carbohydrate which can then be converted into ethanol, algae has almost unlimited applicability. Algae can metabolize various waste streams (such as municipal wastewater, and carbon dioxide from power generation) and produce products with a wide variety of uses. Algae have also demonstrated the ability to manufacture proteins for human and animal consumption. Algae derived fuels from biological carbon fixation are: Biodiesel (transportation fuel, jet-fuel, heating oil), and Bioethanol (E10, E15, E85 FLEX fuel).  Production - Autotrophic Photobioreactors (PBR) and Open-Pond cultivation  12 Bgal/yr of ethanol is produced almost exclusively from corn-based feedstocks  DOE projections of 35 Bgal/yr by 2017 suggests a need for 20 Bgal/yr of ethanol production is required from cellulosic (commercial plants in Iowa and Virginia are expected on-line in 2012) or algae production (pilot and commercial plants are operating in most southern U.S. states). Menetrez, Marc Y., “An Overview of Algae Biofuel Production and Potential Environmental Impact,” (Environmental Science and Technology). Menetrez, M. Y., “The Potential Environmental Impact of Waste from Ethanol Production,” Journal of Air & Waste Management Association, PBR with algae nutrient recycle. Biodiesel Algae to Biofuel Pathways Marc Yves Menetrez U.S. Environmental Protection Agency National Risk Management Research Laboratory Example Algae Constituents (%DW) Algae BiofuelsBioethanol Ethanol Feedstocks References Production – Autotrophic and Heterotrophic Photobioreactors (PBR), Open-Pond and Closed cultivation Biodiesel is made up of lipids which have been processed by transesterification. In addition to common biodiesel feedstock sources such as soybean oil and waste vegetable oil, algae can produce in excess of half their weight in oil, reaching maturity in as little as three to seven days. In addition to corn and cellulosic ethanol, algae can produce ethanol either directly or indirectly. The GMO form of cyanobacteria can directly synthesize ethanol, which then diffuses from the cells into the culture medium and the airspace above it (Algenol Biofuels ). After lipid removal, algae derived carbohydrates can be used to produce ethanol much like corn. Algae Production Risks Algae processes could also have potential human health risks from exposure to allergens, toxins, carcinogens (endotoxins, mycotoxins, proteins, and organic and inorganic chemicals), infection (bacteria, mold, yeast, and GMOs), antibiotics (used to prevent unwanted biological growth), and enzymes (used in process). Additionally, GMO species pose unknown environmental effects that could potentially cause the unintended transfer of transgenes or cause the loss of flora and fauna biodiversity