Accelerated bioremediation of antibiotics and nutrients in complex matrices using self-acclimatized, cost-effective microalgae‑bacteria consortia: a comprehensive comparison with standalone systems.

This study explored the simultaneous removal of major antibiotics (amoxicillin (AMX), ciprofloxacin (CIP), and sulfamethoxazole (SMX)) and nutrients using microalgae, bacteria, and their consortia. To simplify the particular strain maintenance, the consortia were formed by combining microalgae with activated sludge from a sewage treatment plant. In batch studies, antibiotics were set at 1 mg/L, and nutrient concentrations were 1.7 ± 0.1 for phosphate-P, 27.0 ± 2.0 for nitrate-N, and 295.0 ± 5.0 mg/L for chemical oxygen demand (COD). The consortia achieved remarkable removal of 93% for AMX, 72% for CIP, and 20.59% for SMX. During CIP degradation, additional metabolites (m/z 340 and 253) were produced in the consortia system. Microalgae used carotenoids and EPS as protective mechanisms, while the consortia activated catalase (7-11 U/mg protein) to enhance biodegradation. The system removed over 99% of phosphate-P and COD within 12 h, and more than 95% of nitrate-N within one week. The study highlights the potential of consortia (dominated by Proteobacteria, Cyanobacteria, and Tetradesmus) for efficient removal of both antibiotics and nutrients in complex matrices. Overall, consortia reduce the need for aeration and illumination while producing beneficial by-products like EPS and lipids, contributing to more sustainable and cleaner water treatment solutions.