Algae containing 30-75% of lipid by dry basis can be called oilgae. All microalgac species produce lipid however some species can contain up to 70% of their dry weight. Microalgae appear to be the only source of renewable biodiesel that is capable of meeting the global demand for transport fuels. Biodiesel production by using oilgac is an alternative process in contrast to other procedures not only being degradable and non-toxic but also as a solution to global warming via reducing emission gases. Algae-based technologies could provide a key tool for reducing greenhouse gas emissions from coal-fired power plants and other carbon intensive industrial processes. Because algae are rich in oil and can grow in a wide range of conditions, many companies are betting that it can create fuels or other chemicals cheaper than existing feedstocks. The aim of microalgae biofixation of CO2 is to operate large-scale systems that are able to convert a significant fraction of the CO2 outputs from a power plant into biofuels. (C) 2011 Elsevier Ltd. All rights reserved.