Our understanding of the microorganisms involved in in situ biodegradation of xenobiotics, like pesticides, in natural and engineered environments is poor. On-farm biopurification systems (BPSs) treat farm-produced pesticide-contaminated wastewater to reduce surface water pollution. BPSs are a labor and cost-efficient technology but are still mainly operated as black box systems. We used DNA-stable isotope probing (DNA-SIP) and classical enrichment to be informed about the organisms responsible for in situ degradation of the phenylurea herbicide linuron in a BPS matrix. DNA-SIP identified Ramlibacter, Variovorax, and an unknown Comamonadaceae genus as the dominant linuron assimilators. While linuron-degrading Variovorax strains have been isolated repeatedly, Ramlibacter has never been associated before with linuron degradation. Genes and mobile genetic elements (MGEs) previously linked to linuron catabolism were enriched in the heavy DNA-SIP fractions, suggesting their involvement in in situ linuron assimilation. BPS material free cultivation of linuron degraders from the same BPS matrix resulted in a community dominated by Variovorax, while Ramlibacter was not observed. Our study provides evidence for the role of Variovorax in in situ linuron biodegradation in a BPS, alongside other organisms like Ramlibacter, and further shows that cultivation results in a biased representation of the in situ linuron-assimilating bacterial populations.

中文翻译：

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DNA稳定的同位素探测，对不依赖于神经胶质的矿质微生物群进行培养的独立分析及其在农场生物纯化系统中的功能：与富集培养的比较。

我们对在自然环境和工程环境中涉及异种生物原位生物降解的微生物（如农药）的了解很差。农场生物净化系统（BPS）处理农场生产的农药污染的废水，以减少地表水污染。BPS是一种劳动力和成本有效的技术，但仍主要用作黑匣子系统。我们使用DNA稳定同位素探测（DNA-SIP）和经典富集来了解负责BPS基质中苯脲除草剂利尿隆原位降解的生物。DNA-SIP鉴定出Ramlibacter，Variovorax和未知的Comamonadaceae属为主要的线性结合体。尽管已经重复分离了降解利尿隆的Variovorax菌株，但Ramlibacter从未与利尿隆降解相关。先前与亚麻嘧啶分解代谢相关的基因和活动遗传元件（MGE）富含DNA-SIP重组分，表明它们参与了原位亚麻嘧啶同化作用。从相同的BPS基质中无BPS材料的利尿隆降解子的培养导致了以Variovorax为主的群落，而未观察到Ramlibacter。我们的研究提供证据的作用贪噬菌在原位BPS中的利尿隆生物降解，以及其他细菌如Ramlibacter，进一步表明，培养导致原位利尿隆同化细菌种群的偏见。