Enhancement of the immobilization on microalgae protective effects and carbamazepine removal by Chlorella vulgaris

Carbamazepine (CBZ) has drawn extensive attention due to their environmental threats. In this study, polyvinyl alcohol-sodium alginate polymers to immobilize Chlorella vulgaris (FACHB-8) were used to investigate whether immobilization can facilitate microalgae to alleviate the CBZ stress and enhance CBZ removal. The results showed that after immobilized treatment, the biomass of microalgae increased by approximately 20%, the maximum level of malondialdehyde content decreased from 28 to 13 μmol/g, and the photosynthetic capacity of F_V/F_M recovered to 90% of the control group. The CBZ removal rate increased from 67 to 84% by immobilization at a CBZ concentration of 80 mg·L^-1. The results indicated that immobilization technology can effectively protect microalgae from CBZ toxicity and improve the removal of CBZ, especially at high concentrations (> 50 mg/L). Biodegradation was the dominant pathway for microalgae to remove carbamazepine. This study added the understanding of the microalgae responses under immobilization and the interactions between immobilized microalgae and CBZ removal, thereby providing a novel insight into microalgae technology in high concentration wastewater treatments.