Fe₂O₃ nanoparticles drive enhanced composting humification by modulating bacteriophage-bacteria interactions

Area of Science:

• Environmental Microbiology
• Biogeochemistry
• Nanotechnology

Background:

• Bacteria are key in composting, but bacteriophages' role in carbon metabolism is understudied.
• Humic substances (HS) are crucial for soil health and carbon sequestration.
• Iron(III) oxide nanoparticles (Fe2O3 NPs) can influence microbial communities.

Purpose of the Study:

• To investigate the interaction between bacteriophages and bacteria in Fe2O3 NP-amended composting.
• To understand the impact of these interactions on the humification process and carbon metabolism.

Main Methods:

• Integrated metagenomics and untargeted metabolomic analysis.
• Composting experiments with added Fe2O3 NPs.
• Analysis of bacterial community structure and metabolic pathways.

Main Results:

• Fe2O3 NPs increased HS concentration by 27% by day 30.
• Enhanced Bacillota abundance promoted organic matter degradation and activated glycolysis.
• Bacteriophage lysis provided HS precursors and prevented carbon mineralization, increasing HS carbon.
• Fe2O3 NPs accelerated lignin depolymerization, supplying humification precursors.

Conclusions:

• Fe2O3 NPs promote efficient lignocellulose degradation and humification.
• Synergistic action between Bacillota and viral regulation optimizes composting.
• Viral regulation offers a novel strategy for enhancing composting processes.