Enhancing the lab scale biohydrogen production from co-substrates through dark fermentation by bacterial monocultures and bacterial consortium

Abstract Dark fermentative biohydrogen production with other waste biomass needs to be explored as an alternative for sustainable biohydrogen production in future. the biohydrogen production from co-substrates (DW + SCB) using bacterial monocultures and its consortium was performed through dark fermentation in a laboratory scale reactor. Co-substrates are a promising substrate for enhanced biohydrogen production. For the experimental set-up, 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 DW and solid SCB. Total solids, volatile solids, total chemical oxygen demand, soluble chemical oxygen demand, and hydrogen production rate were determined from co-substrates during the dark fermentation process. Morphological 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 8 cumulative hydrogen production of 1098 mL H2/L, HPR of 35.9 mL H2/h/L, and HY of 3.6 mL/H2/gVS(removal) utilizing co-substrates at pH 7.