Extraction of astaxanthin from fresh Haematococcus pluvialis biomass: a sustainable approach using vegetable oils

In this study, we developed an optimized process targeting the key challenges in extracting astaxanthin from fresh H. pluvialis biomass. First, we compared the effectiveness of several commonly used cell disruption methods (acidic and alkaline hydrolysis, ultrasound, enzymatic treatment, and freeze-thaw cycles) on astaxanthin yield and quality. We then evaluated the effects of polar (alcohols: methanol, ethanol, and glycerol) and non-polar solvents (argan, cannabis, and olive oils) on astaxanthin extraction under different conditions (temperature and extraction time). Alkaline treatment with 1% KOH at 65 °C for 15 min provided the highest astaxanthin yield (65 mg/g), and astaxanthin recovery in methanol at 25 ± 1 °C reached 35.36 mg/g after 3 h. A biphasic methanol/olive oil solvent (0.6:1 v/v) enabled recovery of astaxanthin-enriched olive oil with a remarkable concentration of 125 mg/g in the oil phase. This protocol enables efficient astaxanthin extraction from wet biomass, eliminating the need for drying, which often leads to pigment loss, and is readily scalable for industrial applications. The optimized process represents a promising approach for astaxanthin recovery, with potential applications in the cosmetics industry.