Enhancement of fermentative hydrogen production from hydrolyzed water hyacinth with activated carbon detoxification and bacteria domestication

•Activated carbon effectively removed fermentative inhibitors to improve H2 yield.•Removal efficiencies of vanillin and 5-HMF in hydrolysate was over 40%.•H2 yield from water hyacinth increased with AC detoxification and HPB domestication.•Sequential methane yield significantly increased the energy conversion efficiency.

To improve fermentative hydrogen production from water hyacinth pretreated with microwave-assisted dilute H2SO4 and cellulase, activated carbon (AC) was used to effectively remove fermentative inhibitors in hydrolysates. The removal efficiencies of vanillin, 5-hydroxymethyl furfural and furfural in artificial hydrolysates of water hyacinth were 84.8%, 45.4%, and 39.5%, respectively. The glucose content in the hydrolysates decreased by 13.8% with AC treatment. The hydrolysates of water hyacinth were used to domesticate hydrogen producing bacteria (HPB) and improve their adaptability. The hydrogen yield from the hydrolyzed water hyacinth with AC detoxification and HPB domestication increased from 104.0 to 134.9 mL/g total volatile solids (TVS). The sequential methane yield (107.7 mL/g TVS) significantly increased the energy conversion efficiency from 8.5% to 30.9%.