M.H. Sayadi, S. D. Ghatnekar, M. F. Kavian Proceedings of the International Academy of Ecology and Environmental Sciences ISSN 2220-8860 2011 1(2) 112-124 08/2011 International Academy of Ecology and Environmental Sciences biofuel CO2 lipid macroalgae microalgae renewable energy Research on renewable and environmentally friendly fuel is growing rapidly and many scientists and governments are interested to grow it fast due to limitation of conventional fuel sources and their harmful effects on the environment. Biofuels are not only the best and reliably available fuels attained from renewable sources which are environment friendly. Besdies biofuels are abundantly available in all the locations easily accessible and highly sustainable. In the present review, the authors present a brief highlight of challenges that necessitates to be covered in order to make both, micro as well as macro algae a viable option to produce renewable biofuels. It is interesting to note that algae are varied, pervasive, and productive and also having less impact with plants as a food for human and animals. Further research is required to a high quantity of product innovation because most dedicated algae are faced uneconomically high costs. DOI 10.0000/issn-2220-8860-piaees-2011-v1-0011 http://www.iaees.org/publications/journals/piaees/articles/2011-1(2)/Algae-promising-alternative-biofuel.pdf