Abstract
Molecular hydrogen (H 2 ), recognized as an ecologically clean and efficient energy carrier, can also serve as a fuel for biological fuel cells, contributing to sustainable energy conservation. In this study, lignocellulose-containing kitchen residues with a C/N ratio of 7, comprising a mixture of corn, melon, and watermelon (LWM) combined with meat waste (MW), were evaluated to assess the growth and hydrogen (H 2 ) generation of Escherichia coli wild-type and an engineered strain optimized for H 2 production. Compared to the control (peptone + glucose), both microbial biomass and H 2 production were stimulated during fermentation in media containing LWM and MW hydrolysates. Decreases in pH and oxidation-reduction potential (ORP) were monitored during bacterial growth on a mixture of waste substrates. Compared to wild type, ∼ 2-fold enhanced H 2 production was observed in the engineered E. coli mutant strain, with an organic matter removal efficiency of 70%. The results showed that Hyd-3 participates in H 2 production, while Hyd-1 and Hyd-2 enzymes operate in H 2 oxidation. E. coli cells were assessed for their performance as anodic catalysts in the electrochemical fuel cell. Compared to Hyd-1 and Hyd-2 deficient mutant strain, an electrical potential of 0.6 V was recorded for E. coli wild type cells in the electrochemical system, suggesting that Hyd-1 and Hyd-2 involved significantly in electricity generation. The results indicate that LWM supplemented with meat waste serves as an effective and low-cost alternative medium for microbial cultivation, H 2 and bioelectricity production, while also contributing to improved waste management and disposal.