This is not the latest version of this item. The latest version can be found here.
Magnetite Nanoparticles Enhancing H2‐Driven Biomethanation in a Mixed Microbial Community
Author(s)
Date Issued
August 19, 2025
Type
article
Journal
Global Challenges
Volume
9
Issue
9
ISSN
2056-6646
Journal
Global Challenges
Abstract
Biological methanation is increasingly considered for biogas upgrading. Here, the supplementation of conductive magnetite (Fe3O4) nanoparticles is investigated as a strategy to enhance H2-driven biomethanation in a mixed hydrogenotrophic methanogenic community. An enrichment culture, maintained for over 180 days in a fill-and-draw anaerobic bioreactor under H2/CO2 feeding, is used to inoculate batch microcosms containing 0, 1.25, and 2.5 gFe L−1 of magnetite. Magnetite addition resulted in a dose-dependent increase in maximum methane production rates—up to 13-fold compared to controls—and sustained high hydrogen-to-methane conversion yields (78–107%). 16S rRNA gene sequencing reveals that archaeal community composition remained dominated by hydrogenotrophic Methanobrevibacter and Methanobacterium spp., whereas bacterial populations shifted from acetogenic Sporomusa and Acetobacterium spp. toward H2-oxidizing Paracoccus and Thauera spp. at higher magnetite concentrations. Electron microscopy and energy-dispersive X‑ray spectroscopy show that magnetite nanoparticles formed conductive networks bridging microbial cells, and fluorescence in situ hybridization confirmed co-localization of methanogens and Paracoccus within these aggregates. The findings support a direct interspecies electron transfer (DIET) mechanism facilitated by magnetite, whereby Paracoccus spp. oxidize H2 and shuttle electrons to methanogens, accelerating biomethanation. These results highlight the potential of magnetite-mediated DIET to improve power-to-methane processes and advance biogas upgrading technologies.
File(s)![Thumbnail Image]()
Name
Global Challenges - 2025 - Tucci - Magnetite Nanoparticles Enhancing H2‐Driven Biomethanation in a Mixed Microbial.pdf
Size
2 MB
Format
Adobe PDF
Checksum (MD5)
4364da4c958d26020af67b5cbf50ba62