| Energy crisis has been reached the unheard-of levels since the consumption of finite fossil fuel reserves continued to raise exponentially. Renewable resources are turning into the main component in the energy system for sustainable development. Corn stalk, as an abundant agricultural residue, can be transferred into hydrogen to provide a clean and high efficient source of energy. In this paper, the fermentation conditions for the production of hydrogen from liquid cattle manure by mixed strains was investigated. The effects of pretreatment methods of cultures, components of carbon sources, operational pressure, and trace mineral supplements on the yield of hydrogen fermentation were discussed. The fermentation conditions were optimized by the response surface methodology. Furthermore, the hydrogen production capacity of cellulose and hemicellulose from corn stalk with base pretreatment and ionic liquid pretreatment was also studied.The results showed that after alkali-pretreatment or steam-pretreatment of cultures at 100℃for 2050min or at pH9.0 for 24h respectively, the accumulated yield of hydrogen could increase by about 30%. A higher yield of hydrogen was detected when the mixed strains fermented in the medium containing glucose-xylose mixture. At 30 g·L-1 of total sugar concentration and the mass ratio of 1:2 (xylose: glucose), the accumulated yield of hydrogen could increase by 37.4% or 46.1%. When the mixed strains were cultured under a pressure of 40.52 kPa, the amount of accumulated hydrogen in the system is 31.74% higher than that obtained at atmosphere pressure. The addition of hexadecyl trimethyl ammonium bromide (CTAB) of 0.027 g·L-1 resulted in an increment of 29.22% in the accumulated yield of hydrogen. The sequence of the influence on hydrogen yield by these factors was, from highest to lowest, mass ratio of glucose to xylose, operational pressure, and the concentration of CTAB.Furthermore, utility of cellulose and hemicellulose obtained from the pretreatment of corn stalk by 1-butyl-3-methylimidazolium chloride as the medium, a high productivity of 2760 mL·L-1 was achieved at 40 g·L-1 cellulose, and 2700 mL·L-1 was achieved at 25 g·L-1 hemicellulose, which is 32.69% or 36.36% respectively higher than that of cellulose and hemicellulose from alkali-pretreated corn stalk. The co-fermentation of cellulose and hemicellulose obtained better results in the accumulated hydrogen yield and hydrogen production rate. The maximum hydrogen productivity of 3480 mL·L-1 and the maximum production rate of 2700 mL·(L·h)-1 were achieved at the mass ratio of cellulose to hemicellulose of 1:2 and the total carbon source concentration of 45 g·L-1.Based on the results, the optimum conditions of hydrogen fermentation by mixed-strains were at the pressure of 40.52 kPa, the mass ratio of 1:2 (cellulose: hemicellulose) and addition of 0.027 g·L-1 CTAB in the medium, with the steam-pretreatment of mixed strains at 100℃for 30 min. Under these conditions, a hydrogen productivity of 5480 mL·L-1 and production rate of 350 mL·(L·h)-1 were achieved.
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