Using of Chlorella Vulgaris for Livestock Wastewater Treatment and the Expression of NR Gene

Abstract

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 spectrophotometer 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 perday. 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 analysed 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. The transcript of gene at 96 hours in cattle wastewater was higher than BG₁₁ culture medium. These result showed high potentials of Chlorella vulgaris to gene expression related to uptake of toxic nutrient and suitable candidate for gene isolation.Keyword: Algae, Livestock waste water, Nitrate reductase, Transcript.