Integrated PEF–Supercritical CO₂ Technology for High-Purity Astaxanthin Extraction from Haematococcus pluvialis
Hemanth Kumar Manikyam
*
Department of Pharmacology, Chalapathi Institute of Pharmaceutical Sciences, Acharya Nagarjuna University, Guntur-522 034, India.
Sunil K. Joshi
Department of Pediatrics, School of Medicine, University of Miami Miller, Miami, FL, USA.
P. Venkata Suresh
Department of Pharmaceutical Analysis, Chalapathi Institute of Pharmaceutical Sciences, Guntur, Andhra Pradesh- 522034, India.
*Author to whom correspondence should be addressed.
Abstract
Astaxanthin, a high-value xanthophyll carotenoid with potent antioxidant activity, was efficiently extracted from the microalga Haematococcus pluvialis using an integrated green extraction strategy combining pulsed electric field (PEF)-assisted cell disruption and supercritical CO₂ (SC-CO₂) extraction. The study establishes a sustainable and high-efficiency protocol wherein biomass preconditioning via mechanical pulverization and optimized PEF treatment enabled effective permeabilization of the robust sporopollenin-rich cell wall, thereby enhancing intracellular release of esterified astaxanthin. Subsequent extraction using SC-CO₂ at optimized conditions (450–500 bar, 60–65°C) with acetone as a co-solvent significantly improved solubility and recovery of non-polar carotenoids while preserving thermolabile integrity. The process yielded approximately 350 mL of carotenoid-rich oleoresin from 1 kg of dried biomass. Further purification through chloroform–water liquid-liquid partitioning enabled selective enrichment of astaxanthin in the organic phase, resulting in a high-purity extract. Quantitative analysis using a validated HPLC gradient method (ICH Q2 R1 compliant) revealed an astaxanthin concentration of ~9.9% in the final extract, confirming the robustness, reproducibility, and analytical reliability of the developed method. Compared to conventional solvent-based, microwave-assisted, and ultrasonication techniques, the integrated PEF–SC-CO₂ approach demonstrated superior extraction efficiency, reduced solvent toxicity, and enhanced environmental compatibility. This study highlights a scalable, green, and industrially viable extraction platform for high-purity astaxanthin production, with significant implications for applications in nutraceuticals, pharmaceuticals, cosmetics, and aquaculture. The integration of non-thermal cell disruption with supercritical fluid extraction represents a next-generation paradigm in microalgal bioprocessing. Future perspectives include further process intensification, solvent system optimization, and techno-economic scaling for commercial deployment.
Keywords: Astaxanthin, Haematococcus pluvialis, supercritical CO₂ extraction, carotenoids, HPLC quantification, antioxidants