SiO2 nanoparticles (SiO2 NPs) are low-cost, environmentally friendly materials with significant potential to remove pollutants from complex environments. In this study, SiO2 NPs were used for the first time as an additive in aerobic composting to enhance nitrogen retention and reduce the expression of copper resistance genes. The addition of 0.5 g kg-1 SiO2 NPs effectively reduced nitrogen loss by 72.33 % by decreasing denitrification genes (nosZ, nirK, and napA) and increasing nitrogen fixation gene (nifH). The dominant factors affecting nitrification and denitrification genes were Firmicutes and C/N ratio. Additionally, SiO2 NPs decreased copper resistance genes by 28.96 % - 37.52 % in compost products. Copper resistance genes decreased most in the treatment with 0.5 g kg-1 SiO2 NPs. In summary, 0.5 g kg-1 SiO2 NPs have the potential to reduce copper resistance genes and enhance nitrogen retention during aerobic composting, which may be used to improve compost quality.
Keywords: Bacteria community; Denitrification; Nitrification; Nitrogen fixation.
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