Biodegradation of tetracycline antibiotics: Advances and insights into microbial resources, enzymatic mechanisms, and remediation potential.

The extensive use of tetracycline antibiotics (TCs) in human therapy and animal husbandry has resulted in their persistent residues and accumulation across diverse environments, raising substantial global concern. These residues not only accelerate the emergence of antibiotic-resistant pathogens but also pose a long-term ecological risk through the horizontal transfer of antibiotic resistance genes (ARGs). Microbial biodegradation plays a crucial role in the elimination of TCs. Through long-term acclimation and targeted screening, numerous microorganisms exhibiting high degradation capacities have been identified. Recent advances in analytical techniques (e.g., UPLC-Q-TOF-MS) and molecular tools (e.g., 16S rRNA sequencing, whole-genome sequencing, and multi-omics analysis) have progressively elucidated the biodegradation pathways of TCs, key enzymes, and underlying molecular mechanisms. This review systematically summarizes recent progress, with a focus on: (i) a comprehensive inventory of reported TC-degrading microorganisms (including bacteria and fungi), together with an assessment of their respective metabolic traits and application potential; (ii) an in-depth analysis of the key enzymes involved in TC biodegradation, as well as their degradation pathways and catalytic mechanisms; (iii) a critical overview of strategies for identifying novel degrading enzymes; and (iv) a discussion of current technical challenges and prospective research directions. This review aims to provide a robust theoretical foundation and practical insights for the bioremediation of TC contamination and the mitigation of antimicrobial resistance risks.