Comparable biochemical responses of three Scenedesmus species to NiO and ZnO nanoparticles exposure

Today, nanoparticles (NPs) have become intensively used in different fields and subsequently can be also transported to the environment. Investigating the potential toxicity of nanoparticles on algae species supply unique information about ecosystem conditions and promote the safe development of innovative nanotechnology. In the present study, the toxicity of two metal oxide nanoparticles (NiO-NP and ZnO-NP) in Scenedesmus obtusus, S. bernardii and S. obliquus was evaluated. The high dose exposure to the NPs inhibited the algae growth and contents of Chlorophyll a and b. Moreover, lipid peroxidation in three algal species was significantly increased in response to the toxic effects of the NPs. In contrast the total phenol contents of three algal species reduced after treatment with the NPs. Fatty acid profiles changed in the algae species and amount of saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) in S. obliquus and polyunsaturated fatty acids (PUFAs) content in S. bernardii increased. Based on the PUFAs/SFAs ratio, the Ʃn-3/Ʃn-6 ratio, and the cetane number (CN), S. obtusus and S. bernardii appear to be more suitable for nutraceutical production, whereas S. obliquus is more suitable for biodiesel production following the nanoparticles treatment. Considering the rate of ion release from the NPs, there is a close relationship between the toxicity caused by the NPs themselves and the ions released from them.