Removal of antibiotics by four microalgae-based systems for swine wastewater treatment under different phytohormone treatment

This study examined the removal of typical antibiotics from simulated swine wastewater. Microalgae-bacteria/ fungi symbioses were constructed using Chlorella ellipsoidea , endophytic bacteria (S395-2), and Clonostachys rosea as biomaterials. The growth, photosynthetic performance, and removal of three types of antibiotics (tetracyclines, sulfonamides, and quinolones) induced by four phytohormones were analyzed in each system. The results showed that all four phytohormones effectively improved the tolerance of symbiotic strains against antibiotic stress; strigolactones (GR24) achieved the best performance. At 10 -9 M, GR24 achieved the best removal of antibiotics by C. elliptica + S395-2 + C. rosea symbiosis. The average removals of tetracycline, sulfonamide, and quinolone by this system reached 96.2 - 99.4 %, 75.2 - 81.1 %, and 66.8 - 69.9 %, respectively. The results of this study help to develop appropriate bio enhancement strategies as well as design and operate algal-bacterial-fungal symbiotic processes for the treatment of antibiotics-containing wastewater.