Food waste compost assessment via physicochemical analysis and metagenomic profiling

Abstract

Food waste composting offers a sustainable approach for diverting food waste from landfills while producing nutrient-rich soil amendments. However, comprehensive evaluations of compost quality derived from diverse food waste streams remain scarce. This study characterized and compared three in-house food waste composts (Composts A–C), collected from a university, a hotel, and a shopping mall—each with varying feedstock compositions, but produced using the same aerobic composting technology, with a commercially available plant waste compost (Compost D, control). Moisture content, pH, nutrient contents, and microbial communities were determined via shotgun metagenomic sequencing. Compost A exhibited comparable pH (6.31), C/N ratio (14.07), and nutrient levels (N: 3.04, P₂O₅: 0.95, K₂O: 2.74) to the Compost D, suggesting a similar maturity based on physicochemical indicators. Metagenomic analysis revealed that Compost A was predominantly composed of fungi (81.43%), while Compost B (82.88%), C (97.35%) and D (90.84%) were bacterially dominated. Compost A and B were enriched in beneficial taxa—Proteobacteria, Firmicutes, Actinobacteria, Ascomycota, and Basidiomycota—commonly associated with organic matter degradation and nutrient transformation processes. Functional annotation identified genes related to information processing, metabolism, and cellular functions across compost samples, indicating active microbial roles in nutrient cycling. Notably, in-house composts showed lower occurrences of pathogens (Begomovirus, Jasminevirus) and antibiotic resistance genes (e.g., tet(L), ermA) compared to commercial compost. These findings indicate that these in-house food waste composts can exhibit physicochemical and microbial characteristics comparable to commercial compost. Further studies, including field-based assessments, are required to validate their agronomic performance and safety for practical applications.