Optimization of ohmic-assisted thermochemical pretreatment of empty fruit bunch for enhanced hydrogen production and fermentation kinetics

The rising demand for sustainable bioenergy has increased interest in converting lignocellulosic waste, such as empty fruit bunches (EFB), into hydrogen via dark fermentation. However, the dense lignin–carbohydrate matrix of EFB limits enzymatic hydrolysis, sugar release, and microbial conversion, resulting in low hydrogen yields without pretreatment. This study evaluates Ohmic-Assisted Thermochemical Pretreatment (OATP) as a rapid, energy-efficient method for enhancing the digestibility of EFB. The process combines ohmic heating as the thermal driver with a mild alkaline medium (NaOH, 1–5%) to accelerate delignification and hemicellulose solubilization. Response Surface Methodology was applied to optimize NaOH concentration (1–5%), temperature (60–100 °C), and residence time (5–15 min), identifying NaOH concentration and temperature as key factors influencing delignification, sugar release, and hydrogen yield. The optimal condition (3% NaOH, 80 °C, 10 min) achieved 87.4% lignin removal and significantly improved cellulose accessibility. Structural analysis confirmed reduced crystallinity and absence of inhibitory byproducts. Under these conditions, hydrogen yield increased over fivefold, from 47.53 ± 1.90 to 241.49 ± 2.88 mL H2 gVS−1, demonstrating the efficacy of OATP in enhancing biohydrogen production from EFB. Modified Gompertz modeling revealed substantial increases in maximum hydrogen potential (51.6 to 275.6 mL gVS−1) and production rate (0.86 to 4.55 mL gVS−1 h−1). Energy recovery analysis showed a 31-fold improvement in electrical yield (0.10 to 3.17 kWh kg−1 EFB), showing performance comparable to or within the higher range of values reported for selected chemical, thermal, and enzymatic pretreatment approaches under similar conditions. Overall, OATP presents significant potential as a fermentation-compatible pretreatment strategy for enhancing hydrogen-rich bioenergy production from lignocellulosic biomass.

Text 125198.pdf - Published Version Restricted to Repository staff only Download (8MB) | Request a copy Official URL or Download Paper: https://linkinghub.elsevier.com/retrieve/pii/S0961...

Actions (login required)

View Item