growth and pigment development of dunaliella salina teod. in response to ammonium nitrate nutrition

the microalgae, dunaliella salina was isolated from maharlu salt lake, south east of shiraz, iran. the isolated strain was identified by both morphological and physiological markers. the complete its region (its1 + its2) including the 5.8s rdna gene used as molecular marker confirmed our identification. growth and cell proliferation, total chlorophyll and carotenoid contents were determined in the presence of 0.125, 0.25, 0.50, 1.0 and 2.0 mm ammonium nitrate. after five weeks, a maximum cell density of about (4.4 ±0.21)×106 ml-1 was observed in the growth medium containing 1mm nh4no3. increasing nh4no3 concentrations up to 1mm, resulted in an increase in the cells total chlorophyll contents. the highest amount of cell carotenoid contents was produced in media containing the least amount of nh4no3 (0.125 mm).             manipulating the type and amount of external nitrogen sources to induce the synthesis of the highest amounts of carotenoid compounds in this microalgae strain can be of great commercial values to food industries.