Algal treatment was performed for 30 days in three autoclaved livestock wastewaters. Nitrate concentrations in the three batch cultures and autoclaved livestock wastewaters were determined by spectrophotometry method. It was found that the capacity of Chlorella vulgaris removal was reached at rates of 89.22% nitrate in cattle livestock wastewater, 89.34% in sheep livestock wastewater and 89.41% in poultry livestock wastewater. Also, we studied the growth characteristics of C. vulgaris under three wastewater treatments within thirty days. The results showed that in the lag phase, the microalgae was treated in the wastewater with 501.33, 406.66, 381 mg. L-1 nitrate with a biomass productivity of 0.1, 0.09, 0.03g/l per day. On the other hand, we studied the removal of nitrite from wastewater by C. vulgaris. The results showed that the capacity of Chlorella vulgaris for nitrite removal reaches 87.50%, 43%, 65.15%, respectively. Moreover, the expression of nitrate reductase (NR) was analyzed over six days in BG11 medium and livestock wastewater treatment. The highest fold of transcription was observed 96 hours after treatment in both of wastewater and culture medium. These result showed high potentials of Chlorella vulgaris to gene expression related to stress condition of nutrient and suitable candidate for gene isolation.

Keywords