Microalgal cultivation using aquaculture wastewater: Integrated biomass generation and nutrient remediation

Microalgal cultivation using aquaculture wastewater is a promising biorefinary concept for integrated biomass generation and subsequent nutrient removal. In this study, potential of aquaculture wastewater (AWW) as a nutrient substrate for cultivation of Scenedesmus obliquus, Chlorella sorokiniana and Ankistrodesmus falcatus was investigated. Nutrient removal efficiencies were also investigated for selected microalgal strains. Sodium nitrate supplementation strategy is applied to enhance the productivities of biomass, lipid, carbohydrate and protein. Biomass productivities of A. falcatus (198.46 mg L^{− 1} d^{− 1}) with 400 mg L^{− 1} sodium nitrate supplementation and C. sorokiniana (157.04 mg L^{− 1} d^{− 1}) with 600 mg L^{− 1} sodium nitrate supplementation in AWW were comparable to the synthetic medium. Comparable lipid, carbohydrates and proteins productivities were observed in microalgal biomass cultivated using AWW to the productivities in the synthetic medium. Microalgal cultivation in AWW showed removal efficiencies in the range of 86.45–98.21% for ammonia, 75.76–80.85% for nitrate, 98.52–100% for phosphate and 42–69% for COD.