LAUSR

Chlorella vulgaris (C. vulgaris) has attracted widespread attention because of its ability to absorb, enrich, and degrade typical endocrine-disrupting antibiotics (such as levofloxacin) in aquaculture wastewater. However, microplastic pollution in wastewater, which is becoming an increasingly severe problem, will exert a toxic effect on aquatic organisms (such as C. vulgaris and other microalgae). Polystyrene microplastics (PS-MPs), which are commonly found in freshwater aquaculture wastewater, are the most harmful. Therefore, clarifying the effects of PS-MPs on the ability of C. vulgaris to degrade typical endocrine-disrupting antibiotics in freshwater aquaculture wastewater and determining the mechanism of the effect are particularly important. The results of this study showed that under the stress of PS-MPs, the growth of C. vulgaris was significantly inhibited; the EPS-polysaccharide content per algal cell, EPS adsorption, intracellular enrichment and degradation of levofloxacin, total CYP450 content, and total CYP450 activity all decreased; and the relative expression of key genes related to the metabolic activity of algal cells, such as psbA, psaB, and rbcL, was generally downregulated. PS-MPs mainly affected the removal of a typical endocrine-disrupting antibiotic by C. vulgaris by altering adsorption, enrichment, and enzyme degradation. The results provide a reference for research on the impact of microplastic pollution on the treatment of freshwater aquaculture wastewater.