Enhanced antibiotics and antibiotics resistance genes removal from aquaculture wastewater by microalgae-based system induced with plant hormones

This study innovatively investigated the impact of exogenous strigolactone (GR24) addition on the removal of conventional nutrients, representative antibiotics (including tetracyclines (doxycycline hydrochloride and tetracycline hydrochloride), quinolones (ciprofloxacin and norfloxacin), and sulfonamides (sulfadiazine, sulfamethoxazole, and sulfamethoxazole)), and antibiotic resistance genes (ARGs) from aquaculture wastewater using a symbiotic system comprising Chlorella vulgaris (C. vulgaris) + S395-2 + Clonostachys rosea (C. rosea). The results showed that the optimal GR24 concentration was 10⁻⁹ M. At this concentration, the growth and photosynthetic efficiency of the symbiotic system were enhanced. It had the best removal effect on tetracycline antibiotics. The removal rates of total phosphorus, total nitrogen, and chemical oxygen demand reached 84.18% ± 8.26%, 82.24% ± 8.13%, and 78.25% ± 7.63%, respectively. Moreover, it had high removal efficiency and slow rebound for antibiotic resistance genes such as sul2 and inti1. This research provides a new approach for the efficient treatment of aquaculture wastewater, contributing to pollution reduction, water ecosystem protection, and the sustainable development of the aquaculture industry.