Mechanistic insights into microwave-assisted ethyl acetate extraction of natural astaxanthin from Paracoccus sp. for functional products and cost estimation

Abstract

This study investigates a microwave-assisted extraction (MAE) process for the recovery of astaxanthin-rich extract (ARE) from Paracoccus carotinifaciens using ethyl acetate as a recyclable green solvent, integrating mechanistic modeling and techno-economic evaluation. Experimental data combined with computational fluid dynamics (CFD) revealed that microwave-induced thermal gradients and diffusion-driven mass transfer govern pigment release and recovery. Operating conditions (350–400 W; solid–liquid ratio ∼1:30) yielded approximately 40 mg AXT eq./g within 40 min, while preventing thermal degradation. The kinetic model showed strong agreement with experimental data (R² = 0.98). The recovered ARE was successfully incorporated into a lip balm formulation, exhibiting uniform reddish–orange coloration and good stability. A preliminary techno-economic assessment indicated strong economic potential, with a return on investment (ROI) of 168% and a net present value (NPV) of $648.8 million, supporting the potential industrial scalability and economic feasibility of the proposed process. Overall, this work provides a framework combining process optimization, mechanistic understanding, and application potential for the sustainable recovery of microbial carotenoids.