This study investigates the effect of MnO₂-biochar composites (MBC) on promoting humification during chicken manure composting. The results show that MBC significantly increases the concentration of humus and humic acid (HA) by 29.1% and 37.2%, respectively, compared to the control group (CK). MBC also improves the stability of compost products. Hetero two-dimensional correlation spectra indicate that MBC alters the formation mechanism of humus fractions during composting. Random forest analysis reveals that five genera—Microbacterium, Bacteroides, Kroppenstedtia, Gracilibacillus, and Lentibacillus—are significantly related to humus formation. MBC enhances the abundance of these genera during composting, and structural equation modeling confirms their indirect involvement in humus formation through the production of aromatic compounds via secondary metabolism. These genera also directly transform organic components into macromolecular humus structures. The increase in these genera is likely a direct response to the acceleration of humification during MBC composting. These findings suggest that MBC has potential for promoting humification and improving the quality of compost products, which can aid in the harmless disposal of hazardous biowastes. The study highlights the role of MBC in enhancing humification through microbial activity and the formation of aromatic compounds. The results demonstrate that MBC is effective in promoting humification during composting, with the highest performance observed in the MBC treatment. The study also shows that MBC improves the structural composition of humic acid (HA) by enhancing the formation of aromatic carbon skeletons. The addition of MBC alters the bacterial community structure during composting, increasing the relative abundance of key genera involved in humus formation. The study concludes that MBC enhances humification during composting by promoting microbial activity and the formation of aromatic compounds, which are essential for the development of stable humus structures. The findings suggest that MBC has potential for improving the quality and quantity of humus fractions during composting.This study investigates the effect of MnO₂-biochar composites (MBC) on promoting humification during chicken manure composting. The results show that MBC significantly increases the concentration of humus and humic acid (HA) by 29.1% and 37.2%, respectively, compared to the control group (CK). MBC also improves the stability of compost products. Hetero two-dimensional correlation spectra indicate that MBC alters the formation mechanism of humus fractions during composting. Random forest analysis reveals that five genera—Microbacterium, Bacteroides, Kroppenstedtia, Gracilibacillus, and Lentibacillus—are significantly related to humus formation. MBC enhances the abundance of these genera during composting, and structural equation modeling confirms their indirect involvement in humus formation through the production of aromatic compounds via secondary metabolism. These genera also directly transform organic components into macromolecular humus structures. The increase in these genera is likely a direct response to the acceleration of humification during MBC composting. These findings suggest that MBC has potential for promoting humification and improving the quality of compost products, which can aid in the harmless disposal of hazardous biowastes. The study highlights the role of MBC in enhancing humification through microbial activity and the formation of aromatic compounds. The results demonstrate that MBC is effective in promoting humification during composting, with the highest performance observed in the MBC treatment. The study also shows that MBC improves the structural composition of humic acid (HA) by enhancing the formation of aromatic carbon skeletons. The addition of MBC alters the bacterial community structure during composting, increasing the relative abundance of key genera involved in humus formation. The study concludes that MBC enhances humification during composting by promoting microbial activity and the formation of aromatic compounds, which are essential for the development of stable humus structures. The findings suggest that MBC has potential for improving the quality and quantity of humus fractions during composting.