Improved biohydrogen production from lactic acid bacteria contaminating substrates by enriched hydrogen-producing consortium with lactate-fermentation pathway

Abstract

The hydrogen-producing consortium conveying the lactate-fermentation pathway was enriched and used as a co-inoculum with the non-enriched hydrogen-producing consortium for biohydrogen production in the presence of lactic acid bacteria (LAB). The co-inoculum treatment achieved superior hydrogen production performance compared to that of the non-enriched consortium treatment. The effects of enriched consortium concentration, initial pH, and glucose concentration were evaluated, and hydrogen production potential (HP) of 1,605 ± 161 mL-H₂/L and a maximum hydrogen production rate (HPR) of 87.17 ± 15.85 mL-H₂/L.h were achieved under optimal conditions. Biohydrogen production from food waste using the co-inoculum was 1,137 mL-H₂/L from non-autoclaved food waste, corresponding to 56.85 mL-H₂/g-VS_added. Metabolite product and microbial community analyses during food waste fermentation indicated positive cross-feeding activity of hydrogen producers, LAB, and acetogenic bacteria. This study provides valuable information on the use of an efficient, enriched hydrogen-producing consortium to improve biohydrogen production from LAB-contaminated feedstock.