Dark-fermentative biohydrogen production in a glucose-supplemented landfill fresh leachate system

The present study evaluated biohydrogen production in a glucose-supplemented landfill fresh leachate (LFL)-based system through dark fermentation under mesophilic batch conditions. Heat-pretreated anaerobic sludge was used as the inoculum, and changes in biogas production, hydrogen production, pH, volatile fatty acids and ethanol were monitored over 48 h. Maximum biohydrogen and total biogas production reached 320.7 and 867.3 mL/L, respectively, during the initial 12 h, when hydrogen accounted for approximately 37% of the collected gas and the pH decreased to 4.3. Acetate was the predominant measured soluble metabolite during this period. Hydrogen production subsequently declined as the metabolite profile shifted towards increasing butyrate and ethanol concentrations. These temporal relationships suggest that acidification, end-product accumulation and metabolic redirection may have limited later process performance. However, because glucose-free, glucose-only, untreated-inoculum and inhibitor-specific controls were not included, the individual contributions of LFL, glucose, inoculum heat treatment, ammonium and metal ions could not be determined. The results therefore provide a laboratory-scale baseline for an LFL-based, glucose-supplemented fermentation system rather than evidence of the direct or economically viable conversion of raw LFL.