Related Experiment Video
Updated: Apr 18, 2026
07:59
Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors
Published on: December 6, 2018
8.8K
Distinct Denitrification Phenotypes in Closely Related Bacteria: Clues to Understanding Variations in Nitrite
Martin Menestreau1, Daniel A Milligan1, Louise B Sennett1
1Faculty of Chemistry, Biotechnology, and Food Sciences, Norwegian University of Life Sciences, Ås, Norway.
Environmental Microbiology
|April 16, 2026
Summary
Nitrite accumulation varies in denitrifiers due to differences in nitrate and nitrite reductase expression and regulation. Understanding these nitrite (NO2-) handling phenotypes is key for nitrogen removal and mitigating emissions.
Area of Science:
- Microbiology
- Environmental Science
- Biochemistry
Background:
- Nitrite (NO2-) is a crucial intermediate in denitrification, but its accumulation varies among bacterial strains.
- The reasons for transient nitrite accumulation are poorly understood, despite its potential toxicity and role in nitrogen gas emissions.
Purpose of the Study:
- To investigate the causes of varying nitrite accumulation in Stutzerimonas strains.
- To identify the genetic and metabolic factors influencing nitrite handling during denitrification.
Main Methods:
- Profiling of 18 Stutzerimonas strains to categorize them into full, partial, and low nitrite accumulators (FNA, PNA, LNA).
- Analysis of nitrate (NO3-) and nitrite reductase gene expression (NarG, NapA, NirS) and regulatory elements (DnrE).
- Assessing the impact of nitrate addition on nitrite reduction.
Main Results:
- Three nitrite accumulation phenotypes (FNA, PNA, LNA) were identified based on nitrate-N accumulation.
- LNA strains primarily use periplasmic NapA for nitrate reduction, while FNA/PNA strains utilize both NapA and membrane-bound NarG.
- FNA strains showed delayed nirS transcription and unique cytochromes (NirTB) and regulator (DnrE), suggesting complex metabolic control over nitrite reduction.
Conclusions:
- Diverse nitrite-handling phenotypes exist within denitrifiers, driven by variations in reductase expression and regulation.
- Findings offer insights for optimizing wastewater treatment nitrogen removal and developing strategies to reduce nitrous oxide (N2O) emissions from soil.
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