Comparative analysis of hydrogen production and bacterial communities in mesophilic and thermophilic consortia using multiple inoculum sources

This study investigates the hydrogen (H₂) production performance and bacterial communities in mesophilic (37 °C) and thermophilic (50 °C) H₂-producing consortia derived from different inoculum sources and utilizing food waste as a substrate. This study found notable variations in H₂ production characteristics among these consortia. Among the mesophilic consortia (MC), the W-MC obtained with wetland (W) as the inoculum source exhibited the highest hydrogen production (3900 mL·L⁻¹ and 117 mL·L⁻¹·h⁻¹), while among the thermophilic consortia (TC), the FP-TC obtained with forest puddle sediment (FP) as the inoculum source showed the highest performance (2112 mL·L⁻¹ and 127 mL·L⁻¹·h⁻¹). This study reveals that the choice of inoculum source plays a crucial role in determining hydrogen production efficiency. Furthermore, the bacterial community analysis demonstrated varying microbial diversity and richness in different inoculum sources. Clostridium, a well-known H₂-producing bacterium, was found in both mesophilic and thermophilic consortia and showed a positive correlation with H₂ production. Other bacteria, such as Sporanaerobacter, Caproiciproducens, and Caldibacillus, also exhibited significant correlations with H₂ production, suggesting their potential roles in the process. The study highlights the complex interactions between bacterial communities and hydrogen production performance, shedding light on the critical factors influencing this renewable energy source. Overall, this study contributes to our understanding of the microbial ecology and the factors affecting hydrogen production in different temperature conditions, which can have practical implications for optimizing biohydrogen production processes using organic waste substrates.