Work

Soluble Phosphate Additives Remodel Microbial Networks to Accelerate Organic Matter Transformation in Food Waste Composting

Year: 2025

Type: article

Abstract: Phosphates were widely used in composting, but their impact on the degradation of organic matter transformation in food waste compost was not well known. In this study, Ca(H2PO4)2·H2O and K2HPO4 were separately added to food waste for a 30-day composting process. Chemical stoichiometry, high-throughput sequencing, and Mantel analysis were used to reveal the effect of phosphate addition on carbon conversion in composting. Results showed that soluble phosphate addition enhanced compost maturation despite inhibiting crude protein degradation. At the end of composting, the addition of Ca(H2PO4)2·H2O and K2HPO4 resulted in a 33.75% and 45.15% increase in GI compared to the control group. Compared with K2HPO4, Ca(H2PO4)2·H2O addition improved total organic carbon (degradation rate increased by 2.9%) and total volatile solids (increased by 1.13%) degradation while reducing pH (decreased by 0.52), promoting total nitrogen preservation (increased by 25.56%). Microbial co-occurrence networks showed that phosphate increased community complexity and stability, enriching core taxa (Lentilactobacillus, Paraburkholderia, Catelliglobosispora, and Pseudarthrobacter). Mantel tests linked microbial diversity to lipid decomposition and maturation. Random forest analysis revealed that additive soluble phosphate boosted organic matter and lipid degradation by stimulating Tepidisphaera and Thermobifida, while suppressing Lactiplantibacillus. Additionally, soluble phosphate enhanced crude protein degradation via Compostibacillus, Weizmannia, and Ureibacillus enrichment. At the end of composting, Tepidisphaera (14.68%) and Thermobifida (30.62%) had a higher proportion in Ca(H2PO4)2·H2O treatment, which might be an important reason why this treatment was beneficial for organic matter degradation. Overall, Ca(H2PO4)2·H2O achieved the highest maturity and nitrogen retention, proving optimal for food waste composting.

Source: Agronomy

DOI: 10.3390/agronomy15112456