Related Experiment Videos
Why is metabolic labour divided in nitrification?
Engràcia Costa1, Julio Pérez, Jan-Ulrich Kreft
1Department of Chemical Engineering, Autonomous University of Barcelona, ETSE-Campus de la UAB, 08193 Bellaterra (Cerdanyola del Vallès), Barcelona, Spain.
Trends in Microbiology
|April 20, 2006
Summary
Nitrification involves two bacterial groups: ammonia-oxidizers and nitrite-oxidizers. This division optimizes energy production and growth yield, especially in biofilms, potentially leading to bacteria that fully convert ammonia to nitrate.
Area of Science:
- Microbiology
- Biochemistry
- Environmental Science
Background:
- Nitrification, the microbial oxidation of ammonia to nitrate, is a critical process in the nitrogen cycle.
- Historically, Winogradsky's 1890 discovery identified two distinct bacterial groups: ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB).
Discussion:
- This study explores the division of labor in nitrification using the kinetic theory of optimal metabolic pathway design.
- The theory suggests an optimal pathway length exists to maximize Adenosine Triphosphate (ATP) production rate.
- Shortening metabolic pathways can increase bacterial growth rate but may reduce growth yield due to fewer ATP-generating steps.
Key Insights:
- A trade-off exists between growth rate and growth yield in metabolic pathways.
- High growth yield is advantageous for bacteria in clonal clusters, common in biofilms.
- The findings postulate the existence of bacteria capable of completely oxidizing ammonia to nitrate in such environments.
Outlook:
- Further research could investigate the specific metabolic strategies of bacteria in biofilms.
- Understanding these pathways can inform strategies for managing nitrogen cycling in various ecosystems.
- This work provides a theoretical framework for understanding microbial metabolic specialization.