Nickel-Cobalt Oxide Nanoparticle-Induced Biohydrogen Production

Area of Science:

• Biotechnology
• Nanotechnology
• Microbiology

Background:

• Metal oxide nanoparticles (NPs) show promise in enhancing biohydrogen synthesis via dark fermentation (DF).
• The precise mechanisms by which NPs influence DF for improved hydrogen (H2) yield require further elucidation.
• Nickel-cobalt oxide (NiCo2O4) NPs are explored for their potential to optimize H2 production.

Purpose of the Study:

• To investigate the effect of NiCo2O4 NPs on H2 yield during DF.
• To elucidate the underlying mechanisms, including microbial community shifts and gene expression changes, influenced by NiCo2O4 NPs.

Main Methods:

• Synthesis and characterization of NiCo2O4 NPs.
• Fermentation experiments with varying concentrations of NiCo2O4 NPs.
• Analysis of microbial community composition using 16S rRNA sequencing.
• Gene prediction analysis to assess metabolic pathway alterations.

Main Results:

• NiCo2O4 NPs significantly impacted H2 yield, with the highest yield (259.67 mL/g glucose) observed at 400 mg/L, representing a 33.97% increase over the control.
• Microbial analysis revealed a 23.05% increase in the abundance of the H2-producing bacterium *Clostridium sensu stricto 1*.
• Gene prediction indicated an upregulation of pyruvate kinase and other key enzymes involved in glycolysis and H2 evolution.

Conclusions:

• NiCo2O4 NPs are effective in enhancing biohydrogen production through DF.
• The improved H2 yield is attributed to the promotion of H2-producing bacteria and the upregulation of critical metabolic enzymes.
• NiCo2O4 NPs offer a promising strategy for optimizing biohydrogen synthesis.