Interaction effects between light quality and anaerobically digested palm oil mill effluent drives carotenoid and micronutrient accumulation in Chlorella sorokiniana

Microalgae are vital for commercial nutraceuticals, with research focused on optimizing their productivity. This study explores a novel strategy to enhance Chlorella sorokiniana 's nutraceutical potential by combining light-quality manipulation and digested palm oil mill effluent (D-POME) supplementation. The effects of white, red, and blue light and D-POME on calcium, magnesium, beta-carotene, zeaxanthin, and lutein were analyzed. Light quality and D-POME concentration significantly influenced all micronutrient yields except for calcium (p < 0.05). D-POME with blue light increased biomass and magnesium content by 1.4 times as compared to white light, while 50 % D-POME enhanced carotenoids only under red light, favouring lutein (5.8 μg/g DW) and beta-carotene (89.57 μg/g DW). Blue light best promoted biomass growth (0.28 g/L), and intracellular magnesium (1.73 mg/L) whilst calcium content and zeaxanthin content is comparable with white light. This study introduces a sustainable microalgae cultivation approach by repurposing D-POME, reducing waste, and minimizing external inputs, while also demonstrating wavelength-specific nutrient enhancement strategies for optimized nutraceutical production. • Light-and D-POME interactions in microalgae cultivation tunes for nutraceutical type. • Addition of D-POME boosts biomass under blue light and white light up to 2.7 times but inhibits it under red light. • Blue light with 25 % and 50 % addition of D-POME significantly boosts magnesium uptake by 41 % and 21 % increase respectively. • Red light with 50 % D-POME boosts beta-carotene and lutein (p < 0.01), while blue light enhances zeaxanthin (p < 0.01). • Trade-off between biomass and desired nutrient can be tuned using light quality.