Clean water is a vital resource for the sustainability of humankind. Contamination of natural reservoirs by newly emerging pollutants including organic contaminants, microplastics, and nanoparticles are severely increasing in recent times. In the environment, emerging contaminants transported to wastewater treatment plants typically form complex and recalcitrant organic mixtures with other contaminants in wastewater. Thus, the removal or degradation of organic contaminants is mainly dependent on their interactions with other pollutants. Therefore, this study evaluates the ecotoxicological effects of Al2O3NP on a freshwater microalga, S. obliquus. The influence of nanoparticles on the growth and removal capability of microalgae was investigated by assessing several bio-physiological aspects such as growth inhibition, changes in biochemical components, gene expression, and biodegradation capacity for sulfacetamide. The results showed that the addition of 100 mg L-1 of Al2O3NP and 1 mg L-1 of SA decreased total chlorophyll contents of microalga by 23.3% and carotenoids by 21.6% compared to control. The gene expression of five functional genes (psbA, ATPF0C, Lhcb1, and HydA) that are related to the photosynthetic system of S. obliquus were downregulated up to 70, 66, 47, and 65%, respectively, while the Tas gene, which plays a major role in biodegradation of organic xenobiotic chemicals was upregulated up to 369% in the presence of Al2O3NP. Although there was an insignificant influence of Al2O3NP on the removal of sulfacetamide, 8% and 12% removal of sulfacetamide was observed at 50 mg L-1 of Al2O3NP with 1 mg L-1 and 15 mg L-1 of sulfacetamide, respectively compared with 13% and 17% removal in the control. The outcomes of this study have provided a deeper understanding of the impact of Al2O3NP on aquatic ecosystem and confirm the potential of microalgae mediated water treatment system under nanoparticle induced stress.

Influence of nanoparticles on the biodegradation capability of Scenedesmus obliquus

ACS Spring 2022

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