Characteristics of denitrification activity, functional genes, and denitrifying community composition in the composting process of kitchen and garden waste

Zhou Chen; Shenghua Zhang; Yanzeng Li; Yuantao Wang

doi:10.1016/j.biortech.2023.129137

Characteristics of denitrification activity, functional genes, and denitrifying community composition in the composting process of kitchen and garden waste

Bioresour Technol. 2023 Aug:381:129137. doi: 10.1016/j.biortech.2023.129137. Epub 2023 May 8.

Authors

Zhou Chen¹, Shenghua Zhang², Yanzeng Li³, Yuantao Wang³

Affiliations

¹ College of Harbour and Coastal Engineering, Jimei University, Xiamen 361021, People's Republic of China; Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, People's Republic of China; University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China.
² College of Harbour and Coastal Engineering, Jimei University, Xiamen 361021, People's Republic of China. Electronic address: shzhang@jmu.edu.cn.
³ Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, People's Republic of China; University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China.

PMID: 37164228
DOI: 10.1016/j.biortech.2023.129137

Abstract

N₂O can be easily produced during the co-composting of kitchen waste (KW) and garden waste (GW). This study investigated the effects of the co-composting of KW and GW at different ratios (1:2, 1:1.5, 1:1, and 1.5:1) on the denitrifying activities, functional genes, and community composition of denitrifiers. The results showed that the denitrification activity of KW and GW at a 1:2 ratio was the lowest. The gene abundances of nirS, nirK, nosZI, and nosZII were high on days 12 and 28 under the four different ratios. Network analysis demonstrated that nosZ-type denitrifiers could construct a complex and reciprocal bacterial network to promote the reduction of N₂O to N₂. Mantel test results revealed that nirS-, nirK-, nosZI-, and nosZII-type denitrifiers were significantly positively correlated with pH, C/N, and moisture content. These findings demonstrated that composting with appropriate proportions of KW and GW could reduce N₂O emissions caused by denitrification.

Keywords: Denitrification activities; Denitrifying microorganisms; Functional genes; Garden waste; Kitchen waste.

MeSH terms

Bacteria / genetics
Composting*
Denitrification*
Gardens
Nitrous Oxide / analysis
Soil / chemistry
Soil Microbiology

Substances

Nitrous Oxide
Soil