Enhancing biohydrogen production from xylose at low temperature (20 °C) using natural FeS₂ Ore: Thermodynamic analysis and mechanistic insights

This study investigates the efficacy of pyrite in enhancing biohydrogen production from xylose at low temperature (20 °C). Higher hydrogen yield rates (R_m) and reduced lag time (λ) were achieved across initial xylose concentrations ranging from 2-10 g/L. At an optimal xylose concentration of 5 g/L, pyrite reduced λ by 2.5 h and increased R_m from 1.3 to 2.7 mL h^-1. These improvements are attributed to pyrite's ability to enhance the secretion of extracellular polymeric substance and flavins, facilitate NADH and NAD⁺ generation and transition, and favor biohydrogen production. Thermodynamic analyses and Gibbs free energy calculations further elucidated pyrite's role in the full reaction process and rate-limiting steps at low temperature. This study offers valuable insights into improving the efficiency of biohydrogen production at low temperature, with significant implications for energy conservation.