Zhao Liang, Shi Jia, Wang Jingwei, Zhou Hao, Xu Dan, Ma Qiao
College of Environmental Science and Engineering, Institute of Environmental Systems Biology, Dalian Maritime University, Dalian, China.
School of Chemical Engineering, Ocean and Life Science, Dalian University of Technology, Panjin, China.
Appl Environ Microbiol. 2025 Aug 18:e0098425. doi: 10.1128/aem.00984-25.
The antimicrobial agent -chloro--xylenol (PCMX), an emerging environmental pollutant, poses ecological risks; however, its biodegradation mechanisms remain unresolved. Here, we elucidate the metabolic pathway and functional genes involved in the initial catabolic step of PCMX in a newly isolated bacterium, DMU114. Pure-culture and synthetic consortium assays confirmed the pivotal role of in PCMX degradation, despite its relatively low abundance in the PCMX-enriched consortium. Genomic analysis and heterologous expression identified a constitutively expressed flavin-dependent monooxygenase CxyAB as the key enzyme initiating PCMX degradation. High-resolution liquid chromatography-mass spectrometry and nuclear magnetic resonance analyses demonstrated that strain DMU114 degraded PCMX via a potential three-step pathway: -hydroxylation to 4-chloro-3,5-dimethylcatechol, dechlorination to 2-hydroxy-3,5-dimethyl-[1,4]benzoquinone, and dual - and -cleavage of the aromatic ring. Homologs of CxyA are phylogenetically widespread in environmentally relevant genera, including , , , and , indicating their potential role in natural PCMX attenuation. This work provides the first genetic dissection of PCMX mineralization, offering critical insights into its environmental fates and bioremediation strategies targeting antimicrobial contaminants.
The widespread use of the antimicrobial agent -chloro--xylenol (PCMX) in consumer products has raised environmental concerns due to its aquatic toxicity. However, the microbial mechanisms driving its natural breakdown remain poorly understood. This study reveals how a newly isolated bacterium, DMU114, mineralizes PCMX, a process critical for mitigating its ecological risks. This study, for the first time, elucidates the PCMX's complete degradation pathway and identifies the functional genes for its initial conversion step. The degradation gene identified is widespread in environmentally relevant bacteria, suggesting that natural ecosystems may already harbor the potential to neutralize PCMX contamination. These findings advance our ability to predict PCMX's environmental fate and provide a foundation for engineering microbial solutions to combat antimicrobial pollution.
抗菌剂对氯间二甲苯酚（PCMX）是一种新出现的环境污染物，存在生态风险；然而，其生物降解机制仍未得到解决。在此，我们阐明了新分离的细菌DMU114中参与PCMX初始分解代谢步骤的代谢途径和功能基因。纯培养和合成菌群试验证实了[具体内容缺失]在PCMX降解中的关键作用，尽管其在富含PCMX的菌群中丰度相对较低。基因组分析和异源表达确定了一种组成型表达的黄素依赖性单加氧酶CxyAB是启动PCMX降解的关键酶。高分辨率液相色谱 - 质谱分析和核磁共振分析表明，菌株DMU114通过潜在的三步途径降解PCMX：羟基化生成4 - 氯 - 3,5 - 二甲基邻苯二酚，脱氯生成2 - 羟基 - 3,5 - 二甲基 - [1,4]苯醌，以及芳香环的α - 和β - 裂解。CxyA的同源物在系统发育上广泛存在于与环境相关的属中，包括[具体属名缺失]、[具体属名缺失]、[具体属名缺失]和[具体属名缺失]，表明它们在天然PCMX衰减中的潜在作用。这项工作首次对PCMX矿化进行了基因剖析，为其环境归宿和针对抗菌污染物的生物修复策略提供了关键见解。
抗菌剂对氯间二甲苯酚（PCMX）在消费品中的广泛使用因其水生毒性引发了环境问题。然而，驱动其自然分解的微生物机制仍知之甚少。本研究揭示了新分离的细菌DMU114如何使PCMX矿化，这一过程对于减轻其生态风险至关重要。本研究首次阐明了PCMX的完整降解途径，并确定了其初始转化步骤的功能基因。所鉴定的降解基因在与环境相关的细菌中广泛存在，这表明自然生态系统可能已经具备中和PCMX污染的潜力。这些发现提高了我们预测PCMX环境归宿的能力，并为设计对抗抗菌污染的微生物解决方案提供了基础。
