Microalgae-based technology for antibiotic removal from livestock wastewater: A review on mechanisms, performance,...

Wastewater generated by livestock and poultry farming often contains high levels of antibiotic residues, posing substantial environmental risks. In recent years, microalgae-based treatment systems have gained increasing attention as sustainable alternatives to traditional remediation technologies. This review summarizes current advances in understanding antibiotic removal by microalgae, with particular emphasis on the underlying mechanisms and factors governing treatment efficiency. Special attention is given to extracellular polymeric substances (EPS), which function as multifunctional mediators during the removal process. The anionic functional groups within EPS facilitate the bioadsorption of cationic antibiotics, photosensitizing components promote indirect photodegradation, and EPS-associated enzymes participate in direct biotransformation. Synergistic interactions between microalgae and bacteria may further improve antibiotic removal, although the specific mechanisms underlying these interactions remain insufficiently clarified. Despite growing progress, several critical knowledge gaps remain, including inadequate characterization of EPS composition and functionality, as well as limited insight into the behavior of antibiotic transformation products within the EPS matrix. Future advances in this area will require more detailed mechanistic studies, targeted strategies to optimize EPS-mediated removal processes, and comprehensive assessments of treatment performance under practical wastewater conditions.