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

Graphical abstract Highlights • Fe0 nanoparticles (Fe0 NPs) could improve H 2 production from macroalga. • Hydrogen production was enhanced by 6.5 times comparing to control test. • Fe0 NPs promoted hydrogen production and acid accumulation. • Fe0 NPs enriched Clostridium and Terrisporobacter sp. Abstract 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 H 2 /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. [ABSTRACT FROM AUTHOR]