Chloramphenicol (CAP) is an antibiotic that commonly pollutes the environment, and microorganisms primarily drive its degradation and transformation. Although several pathways for CAP degradation have been documented in different bacteria, multiple metabolic pathways in the same strain and their potential biological significance have not been revealed. In this study, WTD-1, which was isolated from activated sludge, can completely degrade 100 mg/L CAP within 60 h as the sole energy source. UPLC-HRMS and HPLC analyses showed that three different pathways, including acetylation, hydroxyl oxidation, and oxidation (C1-C2 bond cleavage), are responsible for the metabolism of CAP. Importantly, acetylation and C3 hydroxyl oxidation reduced the cytotoxicity of the substrate to strain WTD-1, and the C1-C2 bond fracture of CAP generated the metabolite -nitrobenzoic acid (PNBA) to provide energy for its growth. This indicated that the synergistic action of three metabolic pathways caused WTD-1 to be adaptable and able to degrade high concentrations of CAP in the environment. This study deepens our understanding of the microbial degradation pathway of CAP and highlights the biological significance of the synergistic metabolism of antibiotic pollutants by multiple pathways in the same strain.

中文翻译：

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揭示鞘氨醇菌对氯霉素多种代谢途径的生物学意义。 WTD-1

氯霉素（CAP）是一种经常污染环境的抗生素，微生物主要驱动其降解和转化。尽管在不同细菌中已经记录了多种 CAP 降解途径，但同一菌株中的多种代谢途径及其潜在的生物学意义尚未揭示。本研究中，从活性污泥中分离出的WTD-1作为唯一能源，可以在60 h内完全降解100 mg/L CAP。 UPLC-HRMS和HPLC分析表明三种不同的途径，包括乙酰化、羟基氧化和氧化（C1-C2键断裂），负责CAP的代谢。重要的是，乙酰化和C3羟基氧化降低了底物对WTD-1菌株的细胞毒性，CAP的C1-C2键断裂产生代谢物硝基苯甲酸（PNBA）为其生长提供能量。这表明三种代谢途径的协同作用使WTD-1具有适应性并能够降解环境中高浓度的CAP。该研究加深了我们对CAP微生物降解途径的理解，并强调了同一菌株中多种途径协同代谢抗生素污染物的生物学意义。