Advancing sustainable astaxanthin-lipid biorefineries: Robust two-stage phytohormone-driven bioprocess in Chromochloris zofingiensis

Abstract

The increasing demand for natural astaxanthin, a high-value carotenoid, has encouraged research into efficient microalgal production systems. Haematococcus, the dominant producer, faces scalability challenges due to slow growth and low biomass yields. This study presents a robust two-stage mixotrophic bioprocess using Chromochloris zofingiensis as an alternative producer. Gibberellic acid, salicylic acid, and abscisic acid were integrated at concentrations of 5–50 mg/L to optimize yields. GA (50 mg/L) achieved the highest biomass (4.02 g/L), while SA (30 mg/L) resulted in the maximum astaxanthin content (22.25 mg/g) and yield (75 mg/L). Lipid yields increased by 25–28 %, supporting biodiesel co-production. Previous phytohormones-induced bioprocess lacked robust design and adequate metabolic flux. This study addresses critical gaps in previous research by stabilizing metabolic flux and enhancing scalability. The optimized process positions C. zofingiensis as a sustainable platform for commercial astaxanthin-lipid biorefineries, aligning with SDG 12 (responsible consumption) and SDG 3 (health and well-being).