Study On Bio-hydrogen Production From Corn Stalk By Solid State Fermentation

Usually, large quantities of waste water were generated in bio-hydrogen production process owing to employing low concentration of substrate. In order to reduce waste water formation during fermentation hydrogen produce process, the effects of substrate concentration on bio-hydrogen production from com straw were carefully investigated in this study. The result showed that the hydrogen production potential decreased from 104.0 ml·(g-TS)-1 to 49.6 ml·(g-TS)-1 with the increase of substrate concentration changed from 20 g-L-1 to 60 g-L-1. Correspondingly, the VFAs (volatile fatty acid) concentration increased sharply from 4705.23 mg-L-1 to 9374.01 mg-L-1, and the medium pH after hydrogen fermentation decreased from 4.8 to 4.2. From the above, it can be seen that concentration of the substrate played a vital role in the conversion of the corn stalk into bio-hydrogen by solid state fermentation.To improve hydrogen production potential at higher substrate concentration, the key process parameters of bio-hydrogen production from com straw of 60 g·L-1 was optimized in the batch fermentation. Effects of the ambient temperature, initial pH and Na2CO3 on the hydrogen production were investigated further. The maximum hydrogen yield of 78.7 ml·(g-TS)-1 and hydrogen production rate of 2.3 ml H2·(g-TS-h)-1 from com straw of 60 g·L-1 was obtained at initial pH of 8.0±0.1, fermentation temperature of 37±1℃and NaoCO3 addition of 0.06 g-(g-corn stalk)-1 respectively, which were close to the experimental values with a high value of coefficient of determination (R2=0.982). The H2 content in the biogas was 44.3-51.2%(v/v) and there was no significant methane gas observed.