Continuous biohydrogen production from starch wastewater via sequential dark-photo fermentation with emphasize on maghemite nanoparticles

Hydrogen production from starch wastewater via sequential dark-photo fermentation process was investigated. Two anaerobic baffled reactors (ABRs) were operated in parallel at an OLR of 8.11 ± 0.97 g-COD/L/d, and a HRT of 15 h. ABR-1 and ABR-2 was inoculated with pre-treated sludge and sludge immobilized on maghemite nanoparticles, respectively. Better hydrogen yield of 104.75 ± 12.39 mL-H2/g-COD-removed was achieved in ABR-2 as compared to 66.22 ± 4.88 mL-H2/g-COD-removed in ABR-1. The effluent of ABR-2 was used for further hydrogen production by photo fermentation in ABR-3. An overall hydrogen yield of 166.83 ± 27.79 mL-H2/g-COD-removed was achieved at a total HRT of 30 h. 16S rRNA phylogeny showed that Clostridium and Rhodopseudomonas palustris species were dominant in ABR-1, ABR-2 and ABR-3, respectively.