accumulation of beta-carotene in pure microalgae of dunaliella salina and the mixed cultures of caspian sea under nitrogen starvation

beta-carotene is a carotenoid and known as the most famous natural pigment. microalgae are the most important sources for beta-carotene production. due to the high sterilization cost of pure culture, in this study for the first time, growth, amounts of beta-carotene and chlorophyll in caspian sea microalgae under nutrient deficiencies stress, have been measured and compared with pure microalgae of dunaliella salina. the initial and final concentrations of beta-carotene under nitrogen starvation (after 188 hours) was 7.5, 14.8 and 7.0 and 13.5 mol beta-carotene/g protein for pure and mixed culture, respectively. under nitrogen starvation the final protein concentration of microalgae dunaliella salina was increased from 341.8 to 950.1 mg/l. however, for caspian sea mixed microalgae the concentration was reached from 357.1 to 1010.0 mg/l. operating conditions was the same for both samples as follows: ph=7.5, temperature 24-26 ° c and stirring at 160 rpm. this study demonstrated that the accumulated beta-carotene in caspian sea microalgae was comparable to the obtained values of pure microalgae of dunaliella salina. therefore, mixed microalgae culture can be used for beta-carotene production which is preferable and more economical than sterile systems and consequently, the possibility of process industrialization will be increased