초록
<P><B>Abstract</B></P> <P>This paper investigated the improving mechanisms and microbial community dynamics of using zero-valent iron nanoparticles (Fe<SUP>0</SUP> NPs) in hydrogen fermentation of grass. Results showed that Fe<SUP>0</SUP> NPs supplement improved microbial activity and changed dominant microbial communities from <I>Enterobacter</I> sp. to <I>Clostridium</I> sp., which induced a more efficient metabolic pathway towards higher hydrogen production. Meanwhile, it is also proposed that Fe<SUP>0</SUP> NPs could accelerate electron transfer between ferredoxin and hydrogenase, and promote the activity of key enzymes by the released Fe<SUP>2+</SUP>. The maximal hydrogen yield and hydrogen production rate were 64.7 mL/g-dry grass and 12.1 mL/h, respectively at Fe<SUP>0</SUP> NPs dosage of 400 mg/L, which were 73.1% and 128.3% higher compared with the control group. Fe<SUP>0</SUP> NPs also shorten the lag time and facilitated the hydrolysis and utilization of grass. This study demonstrated that Fe<SUP>0</SUP> NPs could effectively improve hydrogen production and accelerate the fermentation process of grass.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fe<SUP>0</SUP> NPs improved H<SUB>2</SUB> production from grass and accelerated fermentation process. </LI> <LI> Improving mechanisms of Fe<SUP>0</SUP> NPs on grass fermentation were analyzed in detail. </LI> <LI> Fe<SUP>0</SUP> NPs supplement changed dominant H<SUB>2</SUB> producer from <I>Enterobacter</I> to <I>Clostridium.</I> </LI> <LI> Fe<SUP>0</SUP> NPs supplement induced a more efficient hydrogen production pathway. </LI> <LI> Fe<SUP>0</SUP> NPs supplement improved the enzymatic activity of dehydrogenase. </LI> </UL> </P>