Experiments with indigenous green algae under varying N and P regimes for revealing their potential in phycoremediation and biomass yield

Abstract

ABSTRACT Three series of experimental treatments were carried out to assess five indigenous green algae for biomass quality, productivity, and phycoremediation potential under varying N, P, NP, and N:P in Bold’s Basal Medium. Algae showed species-specific responses to particular concentrations of N, P, NP, and N:P ratio in the medium. Most species showed their highest yield and productivity in N-varied treatments (2–3 × N with N:P = 3.42–5.13), whereas the lowest yield occurred in P-varied treatments (3–4 × P with N:P = 0.68–0.53). A low N:P from a decrease in N was favourable to Chlamydopodium starrii, whereas a low N:P from an increase of P was favourable to Chlorococcum humicola. A high N:P from an increase of N was favourable to Scenedesmus javanensis. An increase of N:P by adding more N increased the nitrogen removal rate (NRR) of C. humicola and S. javanensis. However, S. javanensis showed the highest phosphorus removal rate (PRR) at low N:P (0.68) from 3 × P in the medium. Algal protein content was directly proportional to the amount of nitrogen in all species except S. javanensis. Chlamydopodium starrii showed the highest protein content at 4 × N in the medium. N starvation stimulated an increase of lipid content in all five microalgae, and the lipid content of C. starrii and Parachlorella kessleri was significantly higher than that of others. Overall, the experiment constitutes a model to identify the optimum nutrient requirements for maximum phycoremediation potential and quality biomass productivity of particular algal species.