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High resistance of a sludge enriched with nitrogen-fixing bacteria to ammonium salts and its potential as a biofertilizer

Lookup NU author(s): Carolina Ospina Betancourth



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2021 by the authors. Licensee MDPI, Basel, Switzerland.The increasing use of chemical fertilizers causes the loss of natural biological nitrogen fixation in soils, water eutrophication and emits more than 300 Mton CO2 per year. It also limits the success of external bacterial inoculation in the soil. Nitrogen fixing bacteria can be inhibited by the presence of ammonia as its presence can inhibit biological nitrogen fixation. Two aerobic sludges from wastewater treatment plants (WWTP) were exposed to high ammonium salts concentrations (>450 mg L−1 and >2 dS m−1). Microbial analysis after treatment through 16S pyrosequencing showed the presence of Fluviicola sp. (17.70%), a genus of the Clostridiaceae family (11.17%), and Azospirillum sp. (10.42%), which were present at the beginning with lower abundance. Denaturing gradient gel electrophoresis (DGGE) analysis based on nif H genes did not show changes in the nitrogen-fixing population. Nitrogen-Fixing Bacteria (NFB) were identified and associated with other microorganisms involved in the nitrogen cycle, presumably for survival at extreme conditions. The potential use of aerobic sludges enriched with NFB is proposed as an alternative to chemical fertilizer as this bacteria could supplement nitrogen to the plant showing competitive results with chemical fertilization.

Publication metadata

Author(s): Rodriguez-Gonzalez C, Ospina-Betancourth C, Sanabria J

Publication type: Article

Publication status: Published

Journal: Bioengineering

Year: 2021

Volume: 8

Issue: 5

Online publication date: 01/05/2021

Acceptance date: 27/04/2021

Date deposited: 08/06/2021

ISSN (electronic): 2306-5354

Publisher: MDPI AG


DOI: 10.3390/bioengineering8050055


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