Effectiveness of Hydrogen Production by Bacteroides vulgatus in Psychrophilic Fermentation of Cattle Slurry.

H₂ is a low-impact energy carrier, which the EU hydrogen strategy has positioned as a major component of energy policy. Dark fermentation by psychrophilic bacteria is a promising avenue of H₂ production, though one that requires further study. The aim of this study was to determine the H₂ production performance of a Bacteroides vulgatus strain during fermentation of psychrophilic cattle slurry. The test strain was isolated from an inland water body at a depth of 40 ± 5 m. The experimental fermentation process was run at 15 ± 1 °C and yielded 265.5 ± 31.2 cm³ biogas/g COD removed, including 46.9 ± 2.6 cm³ H₂/g COD removed. CO₂ was the main constituent of the resultant biogas, at 79.8 ± 1.9%. The gas also contained 17.6 ± 1.4% H₂ and 2.3 ± 0.2% CH₄. Organic matter removal and nutrient take-up from the feedstock were low. Our findings show that practical applicability of this process is hampered by multiple operational hurdles and its relatively poor performance. [ABSTRACT FROM AUTHOR]