Cellular toxicity of cefazolin sodium to the green microalga Chlorella vulgaris: evaluation of biological responses

In recent years, the total consumption of antibiotics to cure infections has widely increased. Consequently, the concentration of antibiotics in aquatic environments has remarkably heightened. Cefazolin sodium (CFZS) is a first-generation cephalosporin antibiotic with significant bactericidal activities. Immense consumption of CFZS for years along with its persistence in various environments led to its growing deposit in different ecosystems. In this study, the model microalga Chlorella vulgaris was chosen to evaluate the impacts of different concentrations of CFZS on aquatic organisms. Notably, the cell number of the microalgae has declined with the rising concentrations of CFZS. Prepared SEM images and flow cytometry charts confirmed the harmful effects of the antibiotic on the cells of C. vulgaris. Furthermore, CFZS caused an increase in the content of pigments (chlorophyll a, b, carotenoids and anthocyanins), level of non-enzymatic antioxidant compounds (total phenol and flavonoid) and activity of enzymatic antioxidants (CAT, SOD and APX) in C. vulgaris. However, C. vulgaris displayed remarkable potential to remove CFZS from the culture medium. The obtained data may shed light on the establishment of the possible risks of antibiotics to algal populations and also microalgae ability in antibiotics removal.