Humic acids (HAs) can function as electron mediators for contaminants transformation in different environments. The humus respiration can facilitate pentachlorophenol (PCP) dechlorination during different biowastes composting. However, different characteristics of synthetic pathways of redox functional groups within HAs during different biowastes composting have never been characterized. Herein, we assessed the synthetic pathways of redox functional groups within HAs from protein-, lignocellulose-, and lignin-rich composts that facilitated the microbially reductive dechlorination of PCP, respectively. The results show that the aromatic systems are the major electron-accepting moieties of HAs and function as electron shuttles to facilitate the PCP dechlorination. Amino acid and reducing sugar are the major precursors for the synthesis of redox functional groups within HAs in protein-rich composts, and polyphenols and amino acids are discerned as the significant components to synthesize redox functional groups of HAs in lignocellulose- and lignin-rich composts. Seven groups of bacterial communities based on relationships among remarkable precursors, key bacterial communities, and redox functional groups within HAs are classified as participants in the precursors' catabolism and aromatic system' anabolism. Furthermore, the significant environmental factors on the synthetic pathways of redox functional groups within HAs in composting are confirmed by structural equation models. Conclusively, the regulating methods for promoting PCP dechlorination by HAs during different biowastes composting are proposed. Our results can help in understanding the distinct formative mechanisms of redox functional groups within HAs during different biowastes composting, providing insights into a classification-oriented approach for recycling utilization of different biowastes.

中文翻译：

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腐殖酸中氧化还原官能团的生物废物源依赖性合成途径有利于堆肥过程中的五氯苯酚脱氯。

腐殖酸（HAs）可以充当电子介质，以在不同环境中转化污染物。腐殖质呼吸可促进不同生物废物堆肥过程中的五氯苯酚（PCP）脱氯。然而，在不同的生物废物堆肥过程中，HAs中氧化还原官能团的合成途径的不同特征从未被表征过。本文中，我们评估了HAs中富含蛋白质，木质纤维素和木质素的堆肥中氧化还原功能基团的合成途径，这些堆肥分别促进了PCP的微生物还原性脱氯。结果表明，芳族体系是HAs的主要电子接受部分，并起电子穿梭的作用，以促进PCP脱氯。氨基酸和还原糖是富含蛋白质的堆肥中HA中氧化还原功能基团合成的主要前体，多酚和氨基酸被认为是合成富含木质纤维素和木质素的堆肥中HA氧化还原功能基团的重要成分。 。根据HA中显着前体，关键细菌群落和氧化还原功能基团之间的关系，将7个细菌群落分类为前体分解代谢和芳族系统合成代谢的参与者。此外，结构方程模型证实了堆肥过程中HAs内部氧化还原功能基团合成途径的重要环境因素。最后，提出了在不同生物废料堆肥过程中HAs促进PCP脱氯的调控方法。我们的结果可以帮助您了解不同生物废物堆肥过程中HA中氧化还原功能基团的独特形成机制，从而为不同生物废物的循环利用提供了一种面向分类的方法。