Enhanced biohydrogen production from macroalgae by zero-valent iron nanoparticles: Insights into microbial and...

In this work, effect of Fe⁰ nanoparticles (Fe⁰ NPs) on macroalgae fermentation was explored. Hydrogen production was significantly enhanced by 6.5 times comparing with control test, achieving 20.25 mL H₂/g VS_added with addition of 200 mg/L Fe⁰ NPs. In-depth analysis of substrate conversion showed that both hydrogen generation and acids accumulation were promoted with Fe⁰ NPs supplementation. Microbial analysis demonstrated that both hydrogen-producing strains belonging to genus Clostridium and Terrisporobacter sp. favorable for acids formation were enriched with Fe⁰ NPs supplementation, while species Acinetobacter lwoffii beneficial to organics mineralization was eliminated. Complex substrate compositions resulted in more prevalent cooperative relationships among species in the system. This study suggested that Fe⁰ NPs plays a crucial role in macroalgae fermentation by affecting the microbial distribution, subsequently influencing the products distribution and energy conversion.