After years of research, the molecular structure of the enzyme responsible for much of the global production of nitrate and nitrogen by bacteria has finally been discovered. The anammox bacteria and other bacteria use this enzyme to convert toxic nitrite into nitrate. Now that the functioning of the enzyme has become clear, new possibilities have opened up for the improved deployment of the anammox bacteria for the production of electricity from wastewater and for the production of rocket fuel. Researchers from Radboud University and the Max Planck Institutes in Heidelberg and Frankfurt have published an article on the subject in Natural microbiology today.
Nitrogen-consuming bacteria like the anammox bacteria need the enzyme nitrite oxidoreductase (NXR) to convert toxic nitrite into nitrate. The enzyme plays a central role in nature’s nitrogen cycle. Significant amounts of ammonium are found in the soil due to activities such as the use of fertilizers. The ammonium is then converted to nitrate, which is soluble in water and therefore easily washed away in groundwater and surface water. This process is an important part of why too much nitrogen has such an impact on the environment.
“Although the enzyme is such a vital part of the nitrogen cycle, we knew relatively little about how it worked,” says Mike Jetten, professor of ecological microbiology at Radboud University. “It took us over ten years to map the molecular structure of this enzyme in the anammox bacteria.”
“NXR turns out to have a complex structure and contains unexpected parts,” explains Thomas Barends of the Max Planck Institute for Medical Research in Heidelberg. “Together with our colleagues in Frankfurt, we have found a building block that ensures that the protein combines into long strands. We also gained a better understanding of how proteins can organize themselves inside a cell in general. “
Wastewater and rocket fuel
Knowledge of the inner workings of NXR will aid in the deployment of the anammox bacteria in interesting applications. Jetten: “Anammox needs this enzyme to grow, but it also grows slowly by nature. We could now remove bottlenecks in the growth process, allowing the bacteria to be applied in smaller, faster facilities. “
Microbiologists in Nijmegen have long studied the properties of this unique anammox bacteria. It is the only known bacteria capable of converting harmful ammonium into harmless nitrogen gas without requiring oxygen in the process. Since its discovery, anammox has been widely used for wastewater treatment.
A year ago, microbiologists discovered that the bacteria could help generate electricity from wastewater. “This previously impossible reaction was made possible by bypassing the NXR enzyme. Effectively: This will cause the bacteria to focus less on growing and more on synthesizing the byproduct hydrazine, one of the compounds used in liquid rocket fuel. ”
Anammox bacteria allow wastewater to be used to generate electricity
Structural and functional characterization of the intracellular filamentous multiprotein complex nitrite oxidoreductase, Natural microbiology (2021). DOI: 10.1038 / s41564-021-00934-8, www.nature.com/articles/s41564-021-00934-8
Quote: Nitrogen production process of the anammox bacteria finally discovered (2021, July 15) retrieved July 15, 2021 from https://phys.org/news/2021-07-nitrogen-Produce-anammox-bacterium-uncovered .html
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