Effect of Hydrogen Peroxide on Hydrogen Production from Melon Fruit (Cucumis melo L.) Waste by Anaerobic Digestion Microbial Community

Biohydrogen (H 2 ) production has the potential to provide clean, environmentally friendly, and cost-effective energy sources. The effect of increasing oxidative stress on biohydrogen production by acid-treated anaerobic digestion microbial communities was studied. The use of varying amounts of hydrogen peroxide (H 2 O 2 ; 0.1, 0.2, and 0.4 mM) for enhancing hydrogen production from melon fruit waste was investigated. It was found that H 2 O 2 amendment to the H 2 -producing mixed culture increased hydrogen production. Treatment with 0.4 mM H 2 O 2 increased cumulative H 2 output by 7.7% (954.6 mL/L), whereas treatment with 0.1 mM H 2 O 2 enhanced H 2 yield by 23.8% (228.2 mL/gVS) compared to the untreated control. All treatments showed a high H 2 production rate when the pH was 4.5 – 7.0.  H 2 O 2 -treated samples exhibited greater resilience to pH reduction and maintained their H 2 production rate as the system became more acidic during H 2 fermentation. The application of H 2 O 2 affected the volatile fatty acid (VFA) profile during biohydrogen fermentation, with an increase in acetic and propionic acid and a reduction in formic acid concentration. The H 2 O 2 treatment positively affects H 2 production and is proposed as an alternative way of improving H 2 fermentation.