Nitrogen Starvation for Lipid Accumulation in the Microalga Species Desmodesmus sp. L. F. Rios & B. C. Klein & L. F. Luz Jr. & R. Maciel Filho & M. R. Wolf Maciel Received: 6 May 2014 /Accepted: 2 October 2014 # Springer Science+Business Media New York 2014 Abstract Recently, to obtain lipids from microalgae has been the object of extensive research, since it is viewed as a promising feedstock for biodiesel production, especially when compared with crops such as soybean and sunflower, in terms of theoretical performance. The reduction of nutrient availability in culture media, especially nitrogen, stresses the microorganisms and affects cell growth, thus inducing lipid accumulation. This is an interesting step in biodiesel feedstock obtention from microalgae and should be better understood. In this study, four levels of nitrogen concentration in the BG-11 culture medium were evaluated in the growth of the chlorophycean microalga Desmodesmus sp. Both cell growth and lipid content were monitored over 7 days of cultivation, which yielded a final cell density of 33×10 6 cells mL -1 with an initial NaNO 3 concentration of 750 mg L -1 in the medium and a maximum lipid content of 23 % with total nitrogen starvation. It was observed that the microalgae presented high lipid accumulation in the fourth day of cultivation with nitrogen starvation, although with moderate cell growth. Keywords Microalgae . Desmodesmus . Biodiesel . Lipids . Nitrogen starvation Introduction Biodiesel is a biodegradable fuel, obtained from renewable sources such as animal fats and vegetable oils. Nowadays, the techniques for large-scale biodiesel production from these type of feedstock are highly developed and economically viable [1]. Lately, lipids extracted from microalgae have been considered as an interesting alternative for biodiesel synthesis, since microalgae can present high biomass productivity and its cultivation does not compete with land used in food production [2, 3]. Appl Biochem Biotechnol DOI 10.1007/s12010-014-1283-6 L. F. Rios (*) : B. C. Klein : R. Maciel Filho : M. R. Wolf Maciel Laboratory of Optimization, Design and Advanced Control/Laboratory of Separation Process Development (LOPCA/LDPS), Faculty of Chemical Engineering, State University of Campinas (Unicamp), Av. Albert Einstein, 500, Campinas, SP, Brazil e-mail: luisa.rpinto@yahoo.com L. F. Luz Jr. Technology Sector, Chemical Engineering Department, Federal University of Paraná (UFPR), Jardim das Américas, Curitiba, PR, Brazil