Analysis of the growth profile, biochemical composition and nutrient removal efficacy of Spirulina sp. NCIM 5143

In the present manuscript, the growth profile of the microalgae Spirulina sp. NCIM 5143 was studied. Screening was performed on four commercial media, i.e., blue‒green-11 (BG-11), Bold’s basal medium (BBM), algal culture medium (ACM), Zarrouk’s medium (ZM), and different concentrations (20%, 40%, 60%, 80%, and 100%) of unsterilized dairy effluent (UDE). Characterization of biomass was performed to assess its biochemical composition through various assays. Elemental composition and bioactive compound analysis were accomplished by inductively coupled plasma-atomic emission spectroscopy (ICP‒AES) and gas chromatography‒mass spectrometry (GC‒MS), respectively. The results revealed that maximum values of most of the parameters, i.e., optical density (0.21), chlorophyll (2.00 mg/l), proteins (119.17 mg/l), and wet (4.06 g/l) and dry biomass weight (0.28 g/l), were found on ZM. For UDE, maximum growth parameters and the highest nutrient removal efficiency were obtained at 100% concentration. Biochemical analysis revealed that total Kjeldahl nitrogen (7.14±0.49%), crude protein (48.23± 3.34%), total antioxidant activity (3.07±0.03 mg AAE/g), and total phenols (8.88±1.93 mg GAE/g) were present in the biomass. Elemental and GC‒MS analysis detected essential micronutrients and many bioactive compounds, respectively. Hence, this study proved that Spirulina sp. NCIM 5143 has the potential for the management of waste dairy effluent. This study also showed its cost-effectiveness, as the dairy effluent analyzed is used without any kind of sterilization. In addition, its biomass is rich in several essential elements, antioxidants, and bioactive compounds of therapeutic and nutraceutical importance.