Irons differently modulate bacterial guilds for leading to varied efficiencies in simultaneous nitrification and denitrification (SND) within four aerobic bioreactors

Xinyu Zhang; Chengli Huang; Weikang Sui; Xiaogang Wu; Xiaojun Zhang

doi:10.1016/j.chemosphere.2024.142216

Irons differently modulate bacterial guilds for leading to varied efficiencies in simultaneous nitrification and denitrification (SND) within four aerobic bioreactors

Chemosphere. 2024 Jun:358:142216. doi: 10.1016/j.chemosphere.2024.142216. Epub 2024 May 3.

Authors

Xinyu Zhang¹, Chengli Huang¹, Weikang Sui¹, Xiaogang Wu¹, Xiaojun Zhang²

Affiliations

¹ State Key Laboratory of Microbial Metabolism, and Joint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
² State Key Laboratory of Microbial Metabolism, and Joint International Research Laboratory of Metabolic & Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China. Electronic address: xjzhang68@sjtu.edu.cn.

PMID: 38705403
DOI: 10.1016/j.chemosphere.2024.142216

Abstract

As a novel biological wastewater nitrogen removal technology, simultaneous nitrification and denitrification (SND) has gained increasing attention. Iron, serving as a viable material, has been shown to influence nitrogen removal. However, the precise impact of iron on the SND process and microbiome remains unclear. In this study, bioreactors amended with iron of varying valences were evaluated for total nitrogen (TN) removal efficiencies under aerobic conditions. The acclimated control reactor without iron addition (NCR) exhibited high ammonia nitrogen (AN) removal efficiency (98.9%), but relatively low TN removal (78.6%) due to limited denitrification. The reactor containing zero-valent iron (Fe0R) demonstrated the highest SND rate of 92.3% with enhanced aerobic denitrification, albeit with lower AN removal (84.1%). Significantly lower SND efficiencies were observed in reactors with ferrous (Fe2R, 66.3%) and ferric (Fe3R, 58.2%) iron. Distinct bacterial communities involved in nitrogen metabolisms were detected in these bioreactors. The presence of complete ammonium oxidation (comammox) genus Nitrospira and anammox bacteria Candidatus Brocadia characterized efficient AN removal in NCR. The relatively low abundance of aerobic denitrifiers in NCR hindered denitrification. Fe0R exhibited highly abundant but low-efficiency methanotrophic ammonium oxidizers, Methylomonas and Methyloparacoccus, along with diverse aerobic denitrifiers, resulting in lower AN removal but an efficient SND process. Conversely, the presence of Fe²⁺/Fe³⁺ constrained the denitrifying community, contributing to lower TN removal efficiency via inefficient denitrification. Therefore, different valent irons modulated the strength of nitrification and denitrification through the assembly of key microbial communities, providing insight for microbiome modulation in nitrogen-rich wastewater treatment.

Keywords: Aerobic denitrifier; Comammox; Functional community; Iron; Nitrogen metabolic genes; Simultaneous nitrification and denitrification.

MeSH terms

Aerobiosis
Ammonia / metabolism
Ammonium Compounds / metabolism
Bacteria* / metabolism
Bioreactors* / microbiology
Denitrification*
Iron* / chemistry
Iron* / metabolism
Microbiota
Nitrification*
Nitrogen* / metabolism
Waste Disposal, Fluid / methods
Wastewater* / chemistry
Wastewater* / microbiology