This study investigated the changes in the fatty acid content and composition in the nitrogen-starved Chlamydomonas reinhardtii starchless mutant. BAF-J5, grown at different temperatures. The optimal temperature for vegetative growth under nitrogen sufficient conditions was found to be 32 degrees C. Shifting temperature from 25 to 32 degrees C, in conjunction with nitrogen starvation, resulted in BAF-J5 storing the maximum quantity of fatty acid (76% of dry cell weight). Shifting to temperatures lower than 25 degrees C, reduced the total amount of stored fatty acid content and increased the level of desaturation in the fatty acids. The optimal fatty acid composition for biodiesel was at 32 degrees C. This study demonstrates how a critical environmental factor, such as temperature, can modulate the amount and composition of fatty acids under nitrogen deprivation and reduce the requirement for costly refining of biofuels. (c) 2012 Elsevier Ltd. All rights reserved.