Effect of indole-3-acetic acid and light-emitting diodes in Skeletonema costatum for producing fucoxanthin and carbon capture under mixotrophic cultivation
摘要
Fucoxanthin, a high-value carotenoid with potential therapeutic applications against obesity, diabetes, and inflammatory diseases, can be efficiently sourced from diatoms such as Skeletonema costatum due to their rapid growth and adaptability. This study optimized fucoxanthin production under mixotrophic conditions by examining the effects of nutrient composition, indole-3-acetic acid (IAA), light-emitting diode (LED) spectra, and CO2 enrichment. Three sequential experiments were conducted: (1) strain screening, identifying S. costatum as the highest fucoxanthin producer among three diatoms; (2) nutrient optimization via Box–Behnken design, revealing a significant synergistic effect between IAA and sodium nitrate; and (3) evaluation of LED spectra and CO2 levels under mixotrophic condition. Glycerol consumption (6.54–84.46%) alongside measurable CO2 fixation confirmed mixotrophic growth. Under optimal conditions, 3 mg L−1 IAA, 200 mg L−1 glycerol, 40 mg L−1 NaNO3, white LED, and 3% CO2, fucoxanthin productivity reached 442.11 µg L−1 day−1 and biomass yield 35.84 mg L−1 day−1, representing a 2.8-fold and 1.6-fold increase, respectively, compared to control (no IAA, air bubbling, white LED). These findings highlight the combined roles of nutrient optimization, light spectrum, and CO2 availability in maximizing fucoxanthin yield, and position S. costatum as a promising candidate for large-scale, sustainable production.