Intensification and optimization of continuous hydrogen production by dark fermentation in a new design liquid/gas hollow fiber membrane bioreactor

A liquid/gas membrane bioreactor (L/G MBR) was developed to intensify the dark fermentation process. hollow fiber module used combine biohydrogen production, in situ liquid–gas separation and hydrogen producing bacteria retention a single unit. The L/G MBR seeded once did not require further microbial input, as consistent average yield of 0.97 ± 0.09 mol-H2/added mol-glucose production rate 106.5 10.6 mL-H2/L-medium/h were reached over year. Different biogas extraction strategies showed that efficient H2 is possible without sweeping gas lumen fibers, thus facilitating purification an industrial setting. Modelling predicted optimal 1.2 mol/mol-glucose added for glucose concentration feed 13.1 g/L, close experimental hydraulic time 8–10 h with organic loading 1.4 g-glucose/L-medium/h. No washout hydrogen-producing observed at low HRT (2 h), suggesting possibility enhancement using optimized rate. Acetate butyrate main metabolites identified. Clostridium Enterobacter dominated liquid outlet. relative abundance pasteurianum increased bioreactor, opposed beijerinckii which more abundant concentration. original configuration enabled testing selection greatly simplified implementation process by addressing its key operational bottlenecks. Indeed, surface served support reservoir across wide range conditions.