초록
<P><B>Abstract</B></P> <P>Bio-hydrogen (H<SUB>2</SUB>) production from renewable biomass has been accepted as a promising method to produce an alternative fuel for the future. In this study, fermentative hydrogen production from cornstalk (CS) hydrolysate pretreated by alkaline-enzymolysis method was investigated. Meanwhile, a five-factor and five-level orthogonal experimental array was designed to study the influences of Ca(OH)<SUB>2</SUB> concentration, alkaline hydrolysis time, alkaline hydrolysis temperature, cellulase and xylanase dosages on cornstalk pretreatment and hydrogen production. A maximum reducing sugar yield of 0.59 g/g-CS was obtained at Ca(OH)<SUB>2</SUB> 0.5%, hydrolysis temperature 115 °C, hydrolysis time 1.5 h, cellulase dosage 4000 U/g-CS and xylanase 4000 U/g-CS. Under this same condition, the maximum hydrogen yields of 168.9 mL/g-CS, 357.6 mL/g-CS, and 424.3 mL/g-CS were obtained at dark-fermentation, photo-fermentation, and two-stage fermentation respectively. It's also found that the significance of these five parameters on H<SUB>2</SUB> production followed from high to low order as: Ca(OH)<SUB>2</SUB> concentration, cellulase dosage, xylanase dosage, hydrolysis time, and hydrolysis temperature. By comparing the energy produced with the energy spent, the maximum Energy Sustainability Index (<I>ESI</I>) value of 1.11 was obtained at the two-stage fermentation. The results suggested that two-stage fermentation is a promising and efficient way for hydrogen production from lignocellulosic biomass.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cornstalk pretreated by Ca(OH)<SUB>2</SUB>-enzymolysis was used for bio-H<SUB>2</SUB> production. </LI> <LI> Parameters of cornstalk pretreatment were optimized by a 5<SUP>5</SUP> orthogonal design. </LI> <LI> A maximum H<SUB>2</SUB> yield of 424.3 mL/g-cornstalk was obtained at two-stage fermentation. </LI> <LI> A maximum <I>ESI</I> value of 1.11 was obtained at two-stage fermentation. </LI> <LI> Two-stage fermentation is a promising way to produce H<SUB>2</SUB> from agricultural biomass. </LI> </UL> </P>