Effects of different concentrations of nitrate and ammonium in medium on growth of the green algae Scenedesmus quadricauda

Since increasing the NO3 and NH4 make eutrophication in waterbodies, microalgae tolerance tohigh concentrations of NO3 and NH4 and their growth in these levels indicate the bioremediationpotential of nitrogen-rich wastewaters and produce efficient algal biomass in freshwaterenvironments. To evaluate the tolerance of green algae, Scenedesmus quadricauda to different NO3and NH4 concentrations, cultivation of S. quadricauda in BBM (Bold Basal’s Medium) werecarried out with seven treatments in triplicates (2.9,15, 25, 50, 75, 100 and 150 mM from NO3 andNH4) at 22 °C in laboratory conditions. Results indicated that this species is able to tolerate 75 mMNO3 and 50 mM NH4 concentrations, although the maximum number of algal cells (32.5×105 cell/ml for NO3 and 25.2×105 cell/ml for NH4), highest algal dry-biomass (1.22 mg/ml for NO3 and1.02 mg/ml forNH4), and the highest specific growth rate (0.098 day-1 for NO3 and 0.082 day-1 forNH4) obtained at 15 mM of NO3 and NH4. Therefore, based on high tolerance to NO3 and NH4levels by S. quadricauda, this species could be used for waterbodies rich in these components. Inaddition, growth capability of this species in these high concentrations illustrated thebioremediation potential of nitrogen-rich wastewaters. On the other hand, with cultivation of thisalga in 15 mM of NO3 and NH4, maximum algal biomass were obtained, therefore, thisconcentration could be used for improving of the chemical composition of BBM culture medium.