Techno-economic and Sustainability Assessment of Integrated Annatto Seed Biorefinery for Natural Pigments, Starch, and Nutraceuticals

Annatto (Bixa orellana L.) seeds, traditionally exploited as a natural pigment source, remain underused despite their richness in bioactive oil and functional carbohydrates. We propose an integrated biorefinery that couples supercritical CO2 oil extraction, ultrasound- and low-pressure solvent-assisted bixin recovery, aqueous starch isolation, and oil encapsulation into nutraceutical powders. Experimental data were scaled with SuperPro Designer to quantify techno-economic performance, and sustainability was assessed using a 12-principle green-extraction metric (Path2Green) to benchmark process choices across environmental, economic, and scalability dimensions. The integrated process achieved a gross margin of 21.8%, ROI 27.9%, NPV USD 5.8 million (7% rate), and a 3–4 year payback time; sensitivity analysis identified feedstock cost and product price as the dominant profitability drivers, while labor and utilities had comparatively minor effects. Sustainability results highlighted the superiority of supercritical CO2 over Soxhlet for oil (solvent safety/recyclability), energy trade-offs between ultrasound and low-pressure solvent extraction for bixin, and the valorization potential of aqueous starch recovery. Collectively, the findings position annatto as a model biomass for zero-waste, circular biorefineries delivering natural pigments, functional carbohydrates, and nutraceutical ingredients through processes that are both economically viable and metrics-driven in sustainability.