Effects of Light on the Growth and β-carotene Accumulation in the Green Algae Dunaliella salina

The marine microalgae Dunaliella salina holds significant economic value due to its rich content of β-carotene, a natural pigment with high antioxidant capacity, immune-stimulating properties, and a crucial role in antioxidant reactions with vitamins C and E. This study evaluated the effects of light factors on the growth and biosynthesis of β-carotene in the Dunaliella salina strain isolated from coastal waters in Central Vietnam. The microalgae strain was cultured in the static f/2 medium at 25°C, under different light spectra (blue, red, and white) and light intensities (13.5, 27.0, and 40.5 µmol photon/m2/s), with a similar light/dark cycle of 16/8. The results indicated that the microalgae strain showed the highest growth rate and production yield of β-carotene under the red LED light, whereas the highest β-carotene accumulation in each microalgal cell was obtained under the blue LED light. Regarding light intensity, the best growth and β-carotene production yield was observed under the highest experimental light intensity of 40.5 µmol photon/m2/s, but the highest β-carotene content per algal cell was reached under the lowest intensity (13.5 µmol photon/m2/s). These findings provide important scientific data for further research to identify the optimal conditions for increasing biomass and stimulating the accumulation of valuable secondary compounds of the microalgae Dunaliella salina in Vietnam.