en Biotechnology Biotechnology پژوهشي Orginal research papers <p>In this study, a native microalgae strain with a high capability of DHA production has been isolated and purified from mangrove shores in the Persian Gulf. Morphological and molecular identification based on 18S rRNA gene showed that the isolated strain belongs to <em>Aurantiochytrium </em>genus. In order to optimize the growth of this strain, various environmental factors were examined, including temperature (15, 20, 25, 30 and 35&deg;C), salinity (10, 30 and 50 g L^-1) and different concentrations of nitrogen sources of yeast extract, peptone, meat extract and monosodium glutamate, each of which was tested at the concentration of 10 g L^-1. The findings show that the optimal growth conditions occur at temperatures of 25-30 &deg;C, pH equal to 6 and in the presence of meat extract as the nitrogen source. In these conditions, the cellular biomass weight, fatty acids and DHA amounts obtained were 7.34, 2.25 and 0.4 g L^-1, respectively. These results imply that the new isolated strain of <em>Aurantiochytrium </em>sp<em>. </em>shy it can be suitable for lipid production.<br> &nbsp;</p> Isolation, Aurantiochytrium sp., Optimization, Biomass, Microalgae, Heterotrophic. 656 671 http://jifro.ir/browse.php?a_code=A-10-2585-1&slc_lang=en&sid=1 M Pahlavan Yali mpahlavanyali@gmail.com 100319475328460030917 100319475328460030917 No ph.d student at iranian fisheries research institute H Jalili hjalili@ut.ac.ir 100319475328460030918 100319475328460030918 Yes Life science engineering Dep. Faculty of New Sciences and Technologies-University of Tehran M Noroozi Noroozi.mostafa@alzahra.ac.ir 100319475328460030919 100319475328460030919 No Biotechnology Dep. Faculty of Biological sciences-Alzahra University Y Morady morady@yahoo.com 100319475328460030920 100319475328460030920 No Seafood Processing & Biotechnological Dep. Iranian Fisheries sciences Research Institue F Saba farkhonde_saba@yahoo.com 100319475328460030921 100319475328460030921 No Biotechnology Dep. Faculty of Biological sciences-Alzahra University