Experimental assessment of lipid yield and phycoremediation potential of five indigenous microalgae under various nutrient regimes (N:P) in BBM

Abstract

The success of the emerging algal fuel industry depends on identifying high-quality species and standardization of their culture protocols for lipid yield and nutrient removal efficiency. The primary objective of the study was to determine the phycoremediation cum lipid-rich biomass production potential of five green microalgae isolated from bloomed freshwaters of Kerala. Three experiments were carried out under various nitrogen and phosphorus content with different N:P. The first experiment included four different treatment levels of N, the second experiment included four different treatment levels of P, and the third experiment had two different treatment levels of N and P together in BBM. Regular BBM was the control. The parameters measured were biomass and lipid productivity, fatty acid composition, biodiesel properties, Nitrogen and Phosphorus removal rate, and efficiency. Chlorolobion braunii appeared productive in N-rich media with high N:P, whereas Monoraphidium contortum in P-rich media with low N:P. Among the five species tested, the latter shows the highest lipid yield and productivity at low N:P in culture media. The lipid content of four species has demonstrated high-quality biofuel properties. The optimum nutrient regimes and N:P for Nitrogen Removal and Phosphorus removal rates were found to be species-specific. Overall, the experiments stand as a model for understanding the influence of variations in N and P concerning N:P on biomass productivity, lipid content, lipid productivity, and N and P removal rate and efficiency of algae for initial standardization of the culture protocols for further industrial trials.