Providing a new cheap medium in terms of biomass and pigment production from Arthrospira maxima is an important issue. In order to determine the effect of nitrogen starvation versus its excess, urea was used as a cheap nitrogen source in two different modes (alternative and additive) at four different concentrations (0, 1.25, 2.5, 5 gL-1 ). It was indicated that an alternative method is better than additive method due to accelerate the ammonia synthesis (NH3) and pH changes in the period of the growth that is directly related to biomass and pigments production. Moreover, the intensive production of biomass concentration, PC, APC, Ca, and C(X+C) content were 1.403, 0.074, 0.093,10.72, and 3.17 mgL-1 with nitrogen starvation medium. Urea considered being one of the inhibition sources of biomass growth due to the formation of NH3. Analyzing final results by general factorial design concluded that omitting nitrogen sources had the potential possibility for growing A. maxima in order to reduce the production costs in large-scale cultivation,which yields better performance than cost-effective Zarrouk’s medium.
