Maximizing microalgal lutein through light patterning and nutrient shifts in photobioreactors

Lutein, a valuable xanthophyll from Chlorella sorokiniana, is vital for ocular and metabolic health. However, lutein degradation under high light or suboptimal nutrient hampers productivity during the growth phase.

This study optimized lutein yield via light modulation (4k-14k lux), intermittent high-intensity (patterned) exposure, and nutrient refinement. Light-dark cycling (18:6, 8k lux) improved the lutein to 65.48 mg L^-1 and increased biomass to 6.12 g L^-1. A patterned 14k lux photobioreactor yielded 69.14 mg L^-1 and 7.01 g L^-1 biomass. Temperature modulation (35 °C) and urea as a nitrogen source under a one-stage bioprocess further increased lutein to 72.45 and 82.60 mg L^-1 and biomass to 6.0-8.0 g L^-1. A two-stage process combining 10k lux light and macro- and micronutrient enrichment achieved a maximum lutein yield of 86.40 mg L^-1 with 8.31 g L^-1 biomass. Compared with the control (62.1 mg L^-1 lutein; 6.75 g L^-1 biomass), the optimized two-stage strategy enhanced lutein production by ~39.1%, while biomass increased by 23.1%, indicating a proportionally higher pigment-to-biomass productivity ratio.

From an economic perspective, the integrated strategy in a two-stage process can reduce costs by 28-32% of lutein, owing to improved nutrient utilization, enhanced energy efficiency in light modulation, and shorter cultivation time. The process thus demonstrates a favorable productivity-to-cost ratio, strengthening the economic feasibility of microalgal lutein production. Integrated light-nutrient strategies effectively enhance lutein production while minimizing degradation. This sustainable approach supports SDG 3 (health), SDG 9 (innovation), and SDG 13 (climate action), paving the way for a scalable microalgae lutein bioprocess. © 2026 Society of Chemical Industry.