Effects of tissue type, cultivar, and pretreatment on oil palm empty fruit bunch biomass chemistry for circular bioeconomy applications

Abstract This study characterizes the physicochemical and structural properties of empty fruit bunch (EFB) biomass from two main oil palm cultivars Elaeis guineensis (E.G.) and its interspecific hybrid Elaeis guineensis × Elaeis oleifera (O × G) to assess its suitability for energy and biochemicals production. Key compositional and structural differences were evaluated across EFB parts (stalks vs. spikelets), and under two different conditions (fresh vs. sterilized). Spikelets exhibited higher calorific values (up to 15,700 kJ/kg), suggesting their potential suitability for thermochemical conversion processes such as combustion, gasification, or pyrolysis. Stalks, which have higher extractives (up to 24%) and ash content (up to 9%), may be considered for processes such as biogas production and hydrothermal liquefaction. Sterilization improved monosaccharide release and marginally reduced inorganic content (magnesium), facilitating bioconversion. The low ash content (less than 5%) and relatively high calorific value of the spikelets suggest that this EFB fraction has potential as a solid biofuel. These findings emphasize the importance of biomass separation and cultivar choice in enhancing downstream processing and promoting circular bioeconomy strategies.