Effects of carbon source variability on enhanced Bio-hydrogen production.

[Display omitted] • Glucose fosters dominance of Clostridium_sensu_stricto_1 , with 235.00 mL H 2 /gVS. • Starch leads to a diverse and stable microbial population, with 234.34 mL H 2 /gVS. • Oil favors fat-degrading Anaerovibrio , hindering H 2 production, with 30.22 mL/gVS. • Propionate accumulation correlates with carbon source complexity. This study investigated how glucose, starch, and rapeseed oil, three common food waste components with diverse molecular and physicochemical characteristics, influenced hydrogen production and microbial communities in dark fermentation under varying carbon/nitrogen (C/N) ratios. The results indicated that glucose and starch groups, significantly increased hydrogen yields to 235 mL H 2 /gVS (C/N = 40) and 234 mL H 2 /gVS (C/N = 40), respectively, while rapeseed oil, with a lower yield of 30 mL H 2 /gVS (C/N = 20), demonstrated a negative impact. Additionally, an accumulation of propionate was observed with increasing carbon source complexity, suggesting that simpler carbon sources favored hydrogen production and bacterial growth. Conversely, lipid-based materials required rigorous pre-treatment to mitigate their inhibitory effects on hydrogen generation. Overall, this study underscores the importance of carbon source selection, especially glucose and starch, for enhancing hydrogen production and microbial growth in dark fermentation, while highlighting the challenges posed by lipid-rich substrates that require intensive pre-treatment to optimize yields. [ABSTRACT FROM AUTHOR]