Available information on passivation effect of biochar on heavy metals (HMs) through regulating bacterial communities remains limited. Thus, this study investigated the correlation between bacterial diversity and HM-fractions (Zn, Cu, Cd, Cr and Pb) during composting with different dose of biochar (5% and 10%, dry weight basis), in order to ascertain the passivation effect on HMs under the influence of bacterial community. The addition of 10% biochar showed better passivation effect with reduction in bioavailability factor (BF) of Zn, Cu, Cd and Pb by 4.10%, 44.12%, 18.75% and 30.06%, respectively. In addition, it brought forward the variation in primary bacterial phylum to the thermophilic phase. The results of redundancy analysis (RDA) and structural equation models (SEMs) indicated that C:N ratio was an important factor in controlling the morphological transformation of HM by affecting the bacterial community structure. Our results maybe provide a novel insight into HM-passivation from an interaction mechanism on C:N ratio and bacterial community.

通过调节细菌群落，生物炭对重金属（HMs）钝化作用的可用信息仍然有限。因此，本研究调查了不同剂量生物炭（5％和10％，干重）堆肥过程中细菌多样性与HM组分（Zn，Cu，Cd，Cr和Pb）之间的相关性，以确定钝化作用在细菌群落的影响下对HMs的作用。添加10％的生物炭表现出更好的钝化效果，同时锌，铜，镉和铅的生物利用度因子（BF）分别降低4.10％，44.12％，18.75％和30.06％。此外，它也将初级细菌门的变异带到了嗜热阶段。冗余分析（RDA）和结构方程模型（SEM）的结果表明，C：氮比是通过影响细菌群落结构来控制HM形态转化的重要因素。我们的研究结果可能从C：N比和细菌群落的相互作用机制为HM钝化提供新的见解。