Phycoremediation of Paracetamol and Tetracycline by Scenedesmus quadricauda: Removal Efficiency and Physiological Responses

Abstract

Pharmaceutical contaminants are increasingly detected in aquatic environments because conventional wastewater treatment often fails to remove them, posing risks to microorganisms, algae, and ecosystem stability. This study evaluated the phycoremediation potential of Scenedesmus quadricauda to remove paracetamol and tetracycline at 3, 6, and 9 mg/L. Removal efficiency was determined by HPLC after 6 and 9 days, while photosynthetic pigments, reactive oxygen species (ROS), malondialdehyde (MDA), proteins, and carbohydrates were measured to assess physiological stress and cellular adaptation. S. quadricauda significantly enhanced pharmaceutical removal compared with controls, with most treatments achieving 100% removal by day 9. Biochemical analyses showed that paracetamol was better tolerated, whereas tetracycline induced greater physiological and oxidative stress, particularly affecting photosynthetic pigments. These findings indicate that S. quadricauda is a promising, low-cost, and environmentally friendly biological agent for pharmaceutical wastewater remediation.