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Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O

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

Nitrificación completa por las bacterias Nitrospira

Holger Daims¹, Elena V Lebedeva², Petra Pjevac¹

¹Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.

|November 27, 2015

Resumen

Los investigadores descubrieron una nueva bacteria capaz de nitrificar por completo, oxidando el amoníaco a nitrato en un solo paso. Este hallazgo desafía la visión de larga data de la nitrificación como un proceso de dos pasos y destaca el papel de Nitrospira en el ciclo del nitrógeno.

Área de la Ciencia:

Microbiología
Ciencias del medio ambiente
La bioquímica

Sus antecedentes:

La nitrificación es crucial para el ciclo del nitrógeno, tradicionalmente visto como un proceso de dos pasos.
Se consideraron distintos los microorganismos responsables de la oxidación del amoníaco y de la oxidación del nitrito.
La ventaja energética de la nitrificación completa sugirió que un solo organismo podría realizar ambos pasos.

Objetivo del estudio:

Para investigar el rompecabezas centenario de la separación funcional en la nitrificación.
Descubrir y cultivar microorganismos capaces de una nitrificación completa.
Comprender la base genética y el significado ecológico de la nitrificación completa.

Principales métodos:

Aislamiento y cultivo de una nueva bacteria del género Nitrospira.
Análisis genómico para identificar las vías metabólicas.
Análisis metagenómico de muestras ambientales.

Principales resultados:

Descubrimiento y cultivo de una bacteria completamente nitrificante dentro del género Nitrospira.
El análisis genómico reveló vías para la oxidación de amoníaco y nitrito en este organismo.
Se encontraron genes para la monooxigenasa de amoníaco y la hidroxilamina deshidrogenasa en Nitrospira y los metagenomas ambientales.

Conclusiones:

La nitrificación completa de Nitrospira desafía el modelo establecido de nitrificación en dos etapas.
Estos organismos son simultáneamente activos en la oxidación del amoníaco en nitrato durante el crecimiento.
Las nitrospiras completamente nitrificantes son actores importantes en las comunidades microbianas que reciclan nitrógeno a nivel mundial.

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