100 / 2023-07-17 18:11:23

Unraveling the impacts of inoculating novel microbial agents on nitrogen conversion during cattle manure composting: Core microorganisms and functional genes

Nitrogen conversion; Composting; Bacterial community; Nitrogen functional gene; Metagenomic

This study investigated the impacts of inoculating with novel microbial agents containing two thermotolerant nitrifying bacteria on nitrogen conversion, bacterial structure and functional genes during cattle manure composting. The results revealed that the addition of microbial agents enhancing the maturation of compost, increased the TN by 13.6-26.8%, reduced NH₃ emission and the N₂O emission by 24.8-36.1% and 22.7-32.1%, respectively. Particularly, the microbial agents mixed Acinetobacter radioresistens and Bacillus nitratireducens (1:1, TG1) had the best nitrogen preservation effect. Furthermore, the inoculation not only produced diverse diazotroph community but also could strength the co-occurrence between core microorganisms to promote nitrogen metabolism. The metagenomic analysis demonstrated that the inoculation decreased the abundance of nitrate reduction gene (nirS, norC, nap and nif), and increased the abundance of hao, thus facilitating nitrification and suppressing NH₃ and N₂O emission.