Efficient ribavirin removal from medical wastewater by microalgae-centric: Microbial biological action and application of double-layer network hydrogel

Pharmaceutical contaminants (PCs) have emerged as a critical class of emerging pollutants in recent decades. Ribavirin (RBV), a broad-spectrum synthetic nucleoside antiviral targeting both RNA and DNA viruses, served as an important therapeutic option for epidemic viral infection. This study employed two distinct freshwater microalgae strains, Scenedesmus sp. SI-35 and Chlorella sp. SI-55, for RBV remediation, coupled with the development of a sustainable microalgae-immobilized hydrogel system with translational potential. The results demonstrated complete RBV removal within 18 days, with no significant shifts in extracellular polysaccharide subtypes under RBV stress. Mechanistic analysis revealed a unique biodegradation pathway mediated primarily by adenosine kinase, distinguishing this process from conventional enzymatic systems such as like cytochrome P450 or glutathione S-transferase. Notably, both two microalgae achieved complete RBV elimination (100%) in actual wastewater systems, where parallel factor analysis unveiled detailed dynamic variations in organic components. Ultimately, a novel microalgae/alginate@ agarose-hydrogel (M/A@A-hydrogel) was successfully engineered, integrating rapid RBV adsorption within its dual-network matrix and sustained biodegradation by immobilized microalgae. These findings highlight the potential of microalgae-based biotechnologies for targeted removal of nucleoside antiviral drugs, with promising extrapolation to broader classes of pharmaceutical contaminants in water treatment systems.