Effect of Fe0 particle size on buffering characteristics and biohydrogen production in high-load photo fermentation system of corn stover.

[Display omitted] • Fe0 was first applied to high-load photo fermentation system of corn stover. • Effects of Fe0 sizes (700, 100 and 50 nm) on hydrogen production were compared. • Fe0 buffered pH, stimulated nitrogenase activity and accelerated acid utilization. • Adding 1000 mg/L Fe0-700 obtained the highest hydrogen yield increment of 92.88 %. The aim of this work was to study the effects of Fe0 particle sizes (700 nm, 100 nm and 50 nm) addition on biohydrogen production, liquid culture characteristics and photosynthetic bacterial respond in the high-load photo fermentation system of corn stover within the concentration range of 200–1500 mg/L. Results showed that Fe0 with particle size of 700 nm had a better promotion effect on hydrogen production than 100 nm and 50 nm. The highest hydrogen yield of 74.32 ± 3.48 mL/g TS and hydrogen production rate of 3.31 ± 0.11 mL/g·h TS corn stover were obtained at 1000 and 1500 mg/L Fe0-700 nm, which were significantly increased by 92.88 % and 133.88 % compared with the control group. Further analysis indicated that Fe0 addition effectively alleviated pH drop, enhanced nitrogenase activity, promoted cell growth, and accelerated the consumption of acetic acid and butyric acid. [ABSTRACT FROM AUTHOR]