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Medicinal Plant Waste as a Sustainable Feedstock for Bioenergy and Climate Change Mitigation

Fauziah Abu Bakar, Mohamad Maulana Magiman, Hassan Alli, Khaoula Laouidi, Chaima Saf, Hassan El Bari

Abstract


The development of the herbal medicine and pharmaceutical sectors has generated increasing amounts of medicinal plant waste (MPW), much of which remains underutilized or is disposed of through unsustainable practices such as open burning and landfilling. MPW contains substantial amounts of lignocellulosic biomass, positioning it as a promising feedstock for renewable energy production and climate change mitigation. This review synthesizes information on the physicochemical properties of MPW and focuses on thermochemical conversion routes, including torrefaction, pyrolysis, gasification, and hydrothermal carbonization. Studies indicate that thermochemical conversion can yield 30–55 wt% bio-oil and 20–35 wt% biochar, while achieving cold gas efficiencies of 55–70%. Hydrothermal treatment can produce hydrochar with carbon contents of 55–65% and higher heating values of 18–23 MJ kg⁻¹. Furthermore, MPW-derived biochar can contribute to carbon sequestration of approximately 2–3 t CO₂-eq per tonne of dry feedstock while enhancing soil water retention and nutrient availability. However, the large-scale valorization of MPW faces several challenges, including feedstock variability, technical constraints, environmental risks, and policy gaps. Recent advances in catalyst design and life cycle assessment provide opportunities to overcome these barriers and improve the sustainability and efficiency of MPW valorization. Overall, the valorization of MPW supports the transition toward a circular bioeconomy, renewable energy, and climate action, thereby contributing directly to Sustainable Development Goal 7 (Affordable and Clean Energy) and Sustainable Development Goal 13 (Climate Action).

Keywords



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DOI: 10.14416/j.asep.2026.09.007

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