Cost-Effective Cultivation of Spirulina platensis Using NPK Fertilizer

A cost-effective fertilizer-based optimum culture medium was formulated for the mass production of Spirulina platensis using NPK-10: 26: 26 complex fertilizer and growth results were compared with several standard culture media. The microalga was grown in an illuminated white LED with 50 mu mol photons m(-2) s(-1) and 30 degrees C temperature under orbital shaking. The optimum NPK fertilizer medium was formulated by varying NPK-10: 26: 26 fertilizer and sodium bicarbonate loading for which maximum biomass growth rate was obtained. The newly formulated fertilizer medium contains NPK-10: 26: 26 (0.76 g l(-1)), sodium bicarbonate (10.0 g l(-1)), sodium chloride (1.0 g l(-1)), and micro nutrients (1.0 ml l(-1)). Maximum growth rate was recorded between 14 and 15 days and corresponding biomass concentration, chlorophyll, protein, and lipid were found to be 1.22, 8.92 g l(-1), 52.35, and 14.84 %, respectively. Above growth results using NPK fertilizer were superior over standard culture media, and 50.0 % cost saving was achieved using newly formulated NPK-10: 26: 26 fertilizer medium for Spirulina growth in comparison to the standard culture media. Uptake of nutrients (i.e., carbon, nitrogen, phosphorous, and potassium) and physicochemical parameters (i.e., pH and conductivity) were measured to monitor Spirulina growth.