The aim of this study was to identify critical driving factors and pathways of mitigating heavy metals (HM) bioavailability during biochar/montmorillonite-amended composting: emphasize on the interaction effect between organic constituents and functional bacteria. Organic components, such as humus (HS), humic (HA) and fulvic acid (FA) and dissolved organic carbon (DOC), exhibited indivisible links with Cu and Zn speciation, which confirmed their vital roles on deactivating Cu and Zn. Network analysis indicated that biochar/montmorillonite obviously increased the diversity of Cu resistant/actor and Zn actor bacteria, which aided in HM passivation. Although multiple pathways were involved in regulating Cu/Zn passivation, the interaction of bacteria and organic constituents was the most critical driving factor. Given that, promoting potential HM resistant/actor bacteria utilizing and transforming low-humification organic fractions coupling with elevating high-humification constituents were the optimal pathway. This study is helpful to practical application of biochar/montmorillonite to inactivate HM for industrial composting.

这项研究的目的是确定生物炭/蒙脱土改良堆肥过程中减轻重金属（HM）生物利用度的关键驱动因素和途径：强调有机成分与功能细菌之间的相互作用。腐殖质（HS），腐殖质（HA）和黄腐酸（FA）和溶解的有机碳（DOC）等有机成分与Cu和Zn形成了不可分割的联系，这证实了它们在钝化Cu和Zn方面起着至关重要的作用。网络分析表明，生物炭/蒙脱石明显增加了耐铜细菌/锌细菌和锌细菌的多样性，这有助于HM钝化。尽管调节铜/锌钝化的过程涉及多种途径，但是细菌和有机成分的相互作用是最关键的驱动因素。鉴于，最佳途径是利用和转化低腐殖质的有机级分并提高高腐殖质的成分来促进潜在的HM抗性/演员细菌。该研究有助于生物炭/蒙脱土在工业堆肥中灭活重金属的实际应用。