High-rate mesophilic hydrogen production from food waste using hybrid immobilized microbiome.

This study examined the feasibility of dark fermentative biohydrogen production from food waste using hybrid immobilization in mesophilic condition. Among four different organic loading rates (OLRs), the highest average hydrogen production rate (HPR) of 9.82 ± 0.30 L/L-d was found at an OLR of 74.7 g hexose/L-d, which was higher than reported values from particulate feedstock in mesophilic condition. The average hydrogen yield (HY) at the condition was 1.25 ± 0.04 mol H/mol hexose. Whereas the average HPR and HY at an OLR 80 g hexose/L-d were 5.82 ± 0.12 L/L-d and 0.64 ± 0.02 mol H/mol hexose, respectively. Metabolic flux analysis showed the low HY was concurrent with the highest propionic acid and homoacetogenis. Bacterial population was shift from Clostridium sp. to non-hydrogen producers including Bifidobacterium, Bacteriodes, Olsenella, Dysgonomonas, and Dialister sp.