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Updated: Aug 14, 2026
08:05
Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
Nitrate and nitrite reduction by microorganisms embedded in a filter paper incubated aerobically
1Département des Sciences du Sol, Institute Agronomique et Veterinaire Hassan II, Rabat, Morocco.
Applied and Environmental Microbiology
|December 1, 1979
Summary
Pseudomonas aeruginosa on filter paper can reduce nitrate and nitrite under aerobic conditions. This process requires a cellulose fiber barrier to limit oxygen, facilitating denitrification by resting cells.
Area of Science:
- Microbiology
- Environmental Science
- Biochemistry
Background:
- Pseudomonas aeruginosa is a versatile bacterium known for its metabolic capabilities.
- Denitrification is a crucial microbial process in nitrogen cycling.
- Understanding microbial processes in confined environments is important for soil and water quality.
Purpose of the Study:
- To investigate the denitrification potential of Pseudomonas aeruginosa under specific aerobic conditions.
- To determine the role of cellulose fiber mesh in facilitating denitrification.
- To elucidate the nitrogen transformation pathways involving nitrate and nitrite reduction.
Main Methods:
- Culturing Pseudomonas aeruginosa on filter paper to steric saturation.
- Incubating resting cells under aerobic conditions with nitrate or nitrite and glucose.
- Utilizing nitrate and nitrite reductaseless mutants to confirm biological reduction.
- Analyzing nitrogen compound accumulation (ammonium, nitrite) in soil-inoculated experiments.
Main Results:
- Pseudomonas aeruginosa reduced nitrate and/or nitrite to facilitate denitrification when confined within cellulose fibers.
- A cellulose fiber mesh was essential for creating an oxygen diffusion barrier, enabling denitrification.
- Denitrification was not observed in large, thick bacterial colonies, highlighting the oxygen limitation.
- Soil inoculations showed accumulation of ammonium and nitrite, with subsequent nitrogen immobilization and mineralization.
Conclusions:
- Pseudomonas aeruginosa can perform denitrification as resting cells under aerobic conditions when oxygen diffusion is limited by a cellulose matrix.
- The physical structure of the growth medium significantly influences the metabolic activity of P. aeruginosa.
- This study provides insights into microbial nitrogen cycling in environments with restricted oxygen availability.
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