Separating and Characterizing Functional Nitrogen Degraders via Magnetic Nanoparticle-Mediated Isolation

Abstract EN

Magnetic nanoparticle-mediated isolation (MMI) is a new method for isolating active functional microbes from complex microorganisms without substrate labeling.

In this study, the composition and properties of magnetic nanoparticles (MNPs) were characterized by a number of techniques, indicating that MNPs have characteristics such as microinterfaces and can be efficiently fixed on the surface of microbial cells.

It also introduced the MMI technology in activated sludge after stable long-term treatment.

With further addition of promotor carbon sources, the enrichment of the functional nitrogen degraders in MMI was significantly higher than in samples without MNPs, showing the advantages of MMI in identifying the active degraders.

Redundancy analysis (RDA) also showed that the functional nitrogen degraders such as Comamonadaceae_unclassified and Thiobacillus absolutely dominated in situ ammonia degradation, and the change in dominant genera had the same trend as the degradation rate of ammonia nitrogen.

In the magnetically functionalized system, the separated functional nitrogen degraders significantly improved ammonia nitrogen degradation efficiency, making it basically stable at more than 80%, up to 91.6%.

These results prove that the complex flora created after the addition of MNPs is more adaptable to newly introduced pollutants, and MMI is a powerful tool for studying pollutant-degrading microorganisms under in situ conditions.