Feedstock-dependent abundance of functional genes related to nitrogen transformation controlled nitrogen loss in composting

• Published in: Bioresource technology 2022-10, Vol.361, p.127678-127678, Article 127678
• Main Authors: Yin, Siqian, Zhang, Wenming, Tong, Tianjian, Yu, Chenxu, Chang, Xinyi, Chen, Kaishan, Xing, Yanhong, Yang, Yingxiang
• Format: Article
• Language: English
• Subjects: Bacteria; Composting; Functional genes; Nitrogen transformation
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2022.127678

[Display omitted] •Map of nitrogen transformation pathway during manure composting was constructed.•Chicken manure had more microbes with ammonification genes and nrfA gene.•Sheep manure contained higher abundance of microbes with denitrification genes.•Nitrogen loss was controlled by nitrogen cycle genes in composting feedstocks.•Genomic analyses revealed key participants in nitrogen cycle during composting. The objective of this work was to explore how selection of feedstock affects nitrogen cycle genes during composting, which eventually determines the nitrogen loss. Four composting mixes (CM: chicken manure; SM: sheep manure; MM1/3: mixed manure with CM: SM = 1:3 w/w, MM3/1: CM: SM = 3:1 w/w) were investigated. Results showed that adding 25 % and 75 % SM to CM reduced 26.5 % and 57.9 % nitrogen loss, respectively. CM contained more ammonification genes and nrfA gene, while SM had more denitrification genes. Nitrogen fixation genes in CM were slightly higher than that in SM at the initial stage, but they sharply dropped off as the composting entered the high temperature stage. MM1/3 showed significantly reduced ammonification genes than CM, and increased nitrogen fixation and NH4+ assimilation genes. Therefore, adding SM to CM could change the abundance of genes and enzymes related to nitrogen cycle to reduce nitrogen loss.