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

Abstract

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.