Biodegradation of tetracycline by Penicillium reticulisporum Te01 under adsorption–metabolism synergy

The widespread application and environmental persistence of tetracycline (TC) in livestock farming cause extensive pollution, threatening human health, ecological stability, and organismal growth. While microbial remediation offers a sustainable route for TC control, the combined mechanisms of fungal adsorption and degradation remain poorly understood. A highly efficient TC-degrading fungus, identified as Penicillium reticulisporum Te01, was isolated from farmland soil. Adsorption analysis followed the Langmuir model, indicating a monolayer process, whereas biodegradation was primarily driven by metabolic activity. The effects of inoculum dosage, initial TC concentration, temperature, and pH were first evaluated through single-factor experiments, and the optimal operational parameters were identified using response surface methodology, resulting in a maximum degradation efficiency of 72.58%. Results demonstrated that Mn²⁺ enhanced TC degradation at specific concentrations; conversely, chlortetracycline and ammonia nitrogen exerted significant inhibitory effects. Ecotoxicity assessment using Chlorella vulgaris revealed increased EC 50 values, confirming a reduction in toxicity after treatment with strain Te01. Additionally, LC–MS characterization identified eight major transformation intermediates to elucidate two plausible biodegradation pathways. These findings reveal, for the first time, the degradation behavior and underlying mechanisms of TC removal mediated by Penicillium reticulisporum Te01. Graphical abstract The alternative text for this image may have been generated using AI.