Microgreen algae have high potential to remove heavy metals from wastewater and to produce biodiesel. In this study, the green algal species Scenesesmus sp. was used to examine the metal uptake and lipids accumulation. The microalga Scenedesmus sp. was grown under continuous regime in the presence of lead (Pb) at concentrations of 0.05, 0.5, 1, 2 and 10 mg/L in a laboratory scale system. All treatments were conducted using autoclaved aqueous solution. Results indicated that Pb inhibited the algal growth with 96h-EC₅₀ of 4.76 mg/L. However, the green alga Scenedesmus sp. could efficiently remove Pb at low concentrations. Lipid accumulation was significantly increased by up to 31% with the addition of Pb at up to 1 mg/L. In contrast, lower heavy metal removal efficiencies and decreasing lipid accumulation were observed in the treatment with the highest concentrations of Pb (10 mg/L).
Results demonstrate that Pb concentrations at above 2 mg/L inhibits the algal growth and subsequently reduces lipid content accumulation in the cell. The present study indicates that the green alga Scenedesmus sp. has the ability to remove Pb from aqueous media and accumulate lipid content, which could be applied in wastewater treatment technology and biodiesel production