Enhancing hydrogen production from anaerobic digestion of pretreated fruit and vegetable peels using Clostridium butyricum NE133

This study aimed to investigate the feasibility of hydrogen production (HP) by Clostridium butyricum NE133 from different fruit and vegetable peels (FVPs) as substrates. In addition, the kinetic parameters of hydrogen production and optimization of the anaerobic dark fermentation conditions were analyzed. Clostridium butyricum NE133 was isolated from domestic wastewater and selected as the front runner hydrogen-producer from glucose with maximum hydrogen production (H_max) of 1778.00 ± 15.03 mL/L, maximum production rate (R_max) of 961.95 mL/L/h and lag phase (λ) of 28.12 h. NE133 was genetically identified (accession number PP581793) and shown to harbor the Fe-Fe hydrogenase gene. This isolate showed a high potential to produce hydrogen from anaerobic fermentation of watermelon peels with H_max of 1062.67 ± 11.92 mL/L, R_max of 268.01 mL/L/h and λ of 33.92 h. The watermelon peels were subjected to different pretreatment methods to enhance the dark fermentation by C. butyricum NE133. It was revealed that the combined physicochemical treatment (0.05 M H₂SO₄/121 °C) significantly increased hydrogen yield, with 2300.33 ± 0.88 mL/L, R_max of 1065.56 mL/L/h and λ of 22.39 h with a high accuracy of R² (0.9999). The study emphasizes the effectiveness of using C. butyricum NE133 for sustainable biohydrogen production. The findings also indicate the feasibility of converting agricultural waste into valuable energy sources, contributing to waste management and renewable energy solutions.