Metagenomics analysis unraveled the influence of sulfate radical-mediated compost nitrogen transformation process

The mechanism of nitrogen transformation of sulfate radical (SO- 4 center dot) in the process of composting is unclear. The objectives of this study were to investigate the influence of SO- 4 center dot on nitrogen biotransformation during composting and to compare the differences in physicochemical parameters and metagenomics analysis between CK (fresh dairy manure and bagasse pith) and PS (the composting raw materials added with potassium persulfate). The results indicated that SO4-center dot guides electron transfer in the conversion of NH4+-N to NO- 3-N and breaches the extracellular polysaccharide (EPS) structure to promote nitrogen removal. Aminomonooxygenase (AMO) and nitrate reductase (NR) levels displayed an interactive relationship between microorganisms and substrates. Metagenomics analysis revealed distinct microbial community compositions and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways between nitrification and denitrification. Correlation analysis indicated that Methanobrevibacter, Bacillus and Pseudomonas were closely related to these processes. This work demonstrates the effect of SO- 4 center dot on nitrogen cycling and retention, and possible mechanisms of nitrification and denitrification during composting.