Evaluating the Technical and Economic Viability of 3-Hydroxypropionic Acid Production from Biomass

This study presents a techno-economic assessment of a conceptual 3-hydroxypropionic acid (3-HP) biorefinery integrating ionic liquid (IL) pretreatment with lignocellulosic biomass conversion. This work provides a novel comparative techno-economic assessment of corn stover (CS) and brewer's spent grain (BSG) as feedstocks for IL-based 3-HP production. A literature-based process model was developed for the continuous production of 50,000 t/year of 3-HP and evaluated using both feedstocks. IL pretreatment was selected for its recyclability and potential to reduce chemical consumption compared with conventional pretreatment methods. Biomass-to-3-HP conversion efficiencies (on a dry basis) of 25.63% and 23.31% were obtained for CS and BSG, respectively, reflecting the lower fermentable sugar recovery achieved from BSG. Economic assessment yielded break-even selling prices (BESP) of $2472/tonne 3-HP for CS and $2643/tonne for BSG, indicating that both configurations are economically competitive with literature-reported bio-based 3-HP values. Sensitivity analysis identified yeast consumption as the dominant cost driver, followed by enzyme and IL requirements. The results highlight the potential of IL-assisted lignocellulosic biorefineries for competitive 3-HP production and identify the optimisation of yeast production and recycling, enhanced IL recovery and recycling, and co-product valorisation through bioethanol and lignin recovery as key opportunities to further reduce production costs.