AUTHOR=Yu Hang , Zhang Xu , Zhao Jingyi , Sun Tiantian , Zhu Yimin 

TITLE=Mechanism of TiO2 nanotube UV-photocatalytic degradation of antibiotic resistance genes in the wastewater sludge and blocking of the transfer

JOURNAL=Frontiers in Environmental Science

VOLUME=Volume 13 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/environmental-science/articles/10.3389/fenvs.2025.1590101

DOI=10.3389/fenvs.2025.1590101

ISSN=2296-665X

ABSTRACT=Antibiotic resistance genes (ARGs) in sludge propagate via horizontal gene transfer (HGT), necessitating advanced mitigation strategies. This study demonstrates TiO2 nanotube UV photocatalysis effectively degrades ARGs (70.6–82.5% reduction) and suppresses HGT by targeting mobile genetic elements (MGEs; 93.4–97.1% removal). Hierarchical TiO2 nanotubes (anatase phase) generated reactive oxygen species (ROS) inducing oxidative DNA damage and cell lysis, preferentially eliminating intracellular ARGs (33.5–46.6% decline) while converting them to extracellular forms. Mobile genetic elements (MGEs) (tnpA-04/intI1) were selectively fragmented via ROS, outperforming HOCl-based systems. Microbial analysis revealed Proteobacteria (e.g., Kofleria) as key ARG hosts, whose decline correlated with resistance reduction (p<0.05). Radiation-resistant Deinococcus dominated post-treatment communities but lacked ARG associations, indicating non-transmissible residual risks. Spatial-specific degradation mechanisms emerged: UV directly fragmented chromosomal ARGs, while ROS oxidized plasmid-borne MGEs, achieving dual ARG elimination and HGT blockade. The intracellular-to-extracellular ARG shift and host-MGE decoupling confirmed transmission disruption. This work establishes TiO2 photocatalysis as a paradigm for sludge treatment, synchronizing ARG removal and environmental risk mitigation through ROS-microbe-DNA interplay.