Property change of bagasse as cell-immobilizing carrier and coproduction of hydrogen-butanol in fixed-bed reactor by repeated cycle fermentation

Property change of bagasse as cell-immobilizing carrier and coproduction of hydrogen-butanol in fixed-bed reactor by repeated cycle fermentation was studied. Bagasse would have potential being used as animal feed after four repeated cycles fermentation lasting for 290 h, because cellulose crystallinity was decreased by 33% and protein content was increased by 187%. Specific surface area and total pore volume of bagasse were also decreased. Maximum accumulated hydrogen production, yield and productivity were 11.7 L/L, 1.89 mol/mol and 537 mL/L/h, respectively. Maximum total solvent (acetone, butanol and ethanol) concentration, solvent yield and solvent productivity were 18.2 g/L 0.31 g/g and 0.78 g/L/h, respectively. Modified Gompertz model was used to describe the hydrogen and butanol production and fitting results showed good agreement with the experimental data. The maximum total product (including hydrogen, acetone, butanol and ethanol) energy and energy conversion efficiency during the 4 cycles fermentation were 758.2 kJ/L and 86.3%, respectively.