Straw-Degrading microbiota Exhibit a pivotal ecological function in pathogen elimination for composting with corn...

A critical barrier to optimizing straw composting is the lack of a defined dose-response relationship between input and biosafety outcomes. Here this study investigated the effects of low (10%, carbon-to-nitrogen (C/N) ratio: 15), medium (30%, C/N ratio: 25) and high (50%, C/N ratio: 35) corn straw additions on pathogen elimination. By integrating eco-modeling and multi-omics, we quantified the microbial community contribution and explored their biological mechanisms. The medium addition ratio showed an optimal performance on pathogen elimination, achieving a 94.6% reduction in pathogen abundance without regrowth. Structural equation modeling indicated that microbial community composition (path coefficient: -0.638) surpassed thermal effects (path coefficient of temperature: -0.534). Under this optimal condition, a specific straw-degrading core microbiota (e.g., Actinomadura, Thermobifida; relative abundance 66.8%) was enriched, exhibiting a significantly broader niche width. This functional consortium exhibited a significant shift in metabolic activity, characterized by the upregulation of lipid/organic acid metabolism and secondary metabolite (such as antibiotics) biosynthesis pathways. These metabolic changes facilitated a combined strategy of competitive exclusion and potential antagonistic interactions, ultimately driving pathogen elimination. This work elucidates a novel mechanism for ensuring compost biosafety by regulating microbial function through resource manipulation, providing a feasible strategy for the simultaneous realization of efficient straw conversion and compost biosafety.