The effect of substrate acidification on the biohydrogen production by dark fermentation.

The modification of substrate concentration and acidification level in inoculum treatment can significantly enhance hydrogen production while reducing costs. Hydrogen production showed a significant variation with food waste (FW) concentration, ranging from 10 to 120 gVS/L. Insufficient acidity at lower FW concentrations of 10, 20, and 40 gVS/L limited hydrogen production to 9.14, 5.70, and 7.78 mL/gVS, respectively, hindering hydrogen-producing bacteria dominance. However, higher FW concentrations facilitated rapid and strong substrate acidification at fermentation onset, effectively inhibiting the non-hydrogen producing bacteria and leading to a vast hydrogen production capacity of 68.63–120.78 mL/gVS. Rapid and substantial FW acidification is vital for effective inoculum treatment, highlighting its crucial role in this study. The findings support the potential use of FW inoculum treatment in generating highly productive microbial communities for hydrogen production. [Display omitted] • Acidification-based inoculum treatment of substrate enables cost-efficient H 2 production. • Variation in hydrogen production observed based on food waste concentrations. • Limited acidity inhibits H 2 production in low food waste concentration groups. • Rapid and strong acidification of substrate is crucial for successful inoculum pretreatment. • Inoculum treatment by food waste can generate productive microbial communities for H 2 production. [ABSTRACT FROM AUTHOR]