Performance of four different microalgae-based technologies in antibiotics removal under multiple concentrations of antibiotics and strigolactone analogue GR24 administration

The formation of symbionts by using different combinations of endophytic bacteria, microalgae, and fungi to purify antibiotics-containing wastewater is an effective and promising biomaterial technology. As it enhances the mixed antibiotics removal performance of the bio-system, this technology is currently extensively studied. Using exogenous supplementation of various low concentrations of the phytohormone strigolactone analogue GR24, the removal of various antibiotics from simulated wastewater was examined. The performances of Chlorella vulgaris monoculture, activated sludge–C. vulgaris–Clonostachys rosea, Bacillus licheniformis–C. vulgaris–C. rosea, and endophytic bacteria (S395-2)–C. vulgaris–C. rosea co-culture systems were systematically compared. Their removal capacities for tetracycline, oxytetracycline, and chlortetracycline antibiotics from simulated wastewater were assessed. Chlorella vulgaris–endophytic bacteria–C. rosea co-cultures achieved the best performance under 0.25 mg L⁻¹ antibiotics, which could be further enhanced by GR24 supplementation. This result demonstrates that the combination of endophytic bacteria with microalgae and fungi is superior to activated sludge–B. licheniformis–microalgae–fungi systems. Exogenous supplementation of GR24 is an effective strategy to improve the performance of antibiotics removal from wastewater.