Astaxanthin: nature's multifunctional molecule, natural sources, health benefits, and process advancements.

Astaxanthin, a natural di-keto carotenoid xanthophyll, is a highly valued nutraceutical and food ingredient due to its potent health benefits, including: anti-inflammatory, antioxidant, anti-cancer, cardiovascular, and anti-diabetic effects. This review examines the primary natural sources of: astaxanthin microalgae, yeast, bacteria, and plants, with a focus on microalgae due to their superior accumulation potential and bioactivity. It explores the growing prospects for large-scale astaxanthin production, highlighting advancements in both upstream and downstream processes. Upstream innovations include enhanced bioprocess designs that improve biomass yield, light and stress tolerance. Downstream, sustainable extraction methods such as aqueous two-phase systems with deep eutectic solvents (99.64% recovery) and high-pressure supercritical CO₂ extraction have improved efficiency and scalability. Additionally, eco-friendly techniques, such as bead milling and pulsed electric field permeabilization offer cost-effective solutions, among other cell disruption techniques, and ensure higher yields. This study provides a comprehensive overview of recent advances in astaxanthin production and extraction, aligned with the Sustainable Development Goals (SDGs) linked to health and well-being (SDG 3) and responsible consumption and production (SDG 12).