Biological hydrogen production from mixed culture using aeration pretreatment

Recently, a two-step process has been proposed where in the first step biohydrogen is produced (together with volatile fatty acids) and in the second one the volatile fatty acids are used as substrate for biological methane production. The aims of the present study were: evaluate the use of the aerobic stress to develop a hydrogen-producing biomass; evaluate the “stability” of the hydrogen-producing biomass (i.e. if hydrogenotrophic methanogens regrowth was observed); evaluate the methane production using as substrate the VFA produced during the hydrogen production processes. Anaerobic granular sludge and glucose were used as inoculum and substrate, respectively. The results confirm the possibility of using an aerobic stress for the selection of a hydrogen-producing biomass: hydrogenotrophic-methanogenic activity was not observed for the duration of the experiments. The VFA produced during the hydrogen production processes can be promptly used as substrate by methanogens.