Biohydrogen production from co-substrates through dark fermentation by bacterial consortium

Hydrogen is a clean energy carrier that can be used as fuel for fuel cells. Dark fermentative biohydrogen production with other waste biomass needs to be explored as an alternative for sustainable biohydrogen production in future. In this study, lab-scale bioreactor were carried out to produce biohydrogen from co-substrates using bacterial consortium at 37 ℃. For the experimental setup, a 1-L-working-volume reactor was used for biohydrogen production by bacterial monocultures and consortium on co-substrates. A batch experiment was performed at 37 °C with an initial pH of 7.0 and a mixing ratio of 600:300 between dairy whey and sugarcane bagasse. Total solids (TS), volatile solids (VS), total chemical oxygen demand (TCOD), soluble chemical oxygen demand (SCOD), and hydrogen production rate (HPR) were determined from co-substrates during the dark fermentation process. Morphologic changes of biohydrogen producing bacteria binds on co-substrates after the fermentation process were determined using SEM imaging. The bacteria can degrade the substrate when they attach to it causing hole formation and cracked the surface area. The level of biohydrogen production by bacterial consortium was observed and the results revealed a hydrogen production rate of 35.9 mL H₂/L/h. In fermentative H₂ production, it is quite similar to that of most H₂-producing bacteria previously studied, especially that of the bacterial consortium, and this indicates that the attempt to find an outstanding bacterial strain for fermentative H₂ production might be very difficult if not impossible.