Creatinine combined with light increases the contents of lutein and β-carotene, the main carotenoids of Dunaliella bardawil.

Dunaliella bardawil, a unicellular green alga, can accumulate a large amount of lutein and β-carotene under stresses. Using chemical inducers combined with abiotic stress to promote the accumulation of high value-added products such as lipids and carotenoids in microalgae has attracted more and more attention. In this study, creatinine was added into autotrophic medium to investigate its effects on the growth, chlorophyll content, and the ingredients and content of carotenoids in D. bardawil. The results showed that creatinine alone could significantly increase the biomass, chlorophyll and carotenoid contents of D. bardawil, among which the contents of lutein and β-carotene were further increased, while the content of zeaxanthin was decreased. In order to further improve the content of the two carotenoids, different light intensities combined with creatinine have been adopted. Under 6.589 W/m light intensity, creatinine could effectively increase the production of lutein, zeaxanthin, α-carotene and β-carotene. Compared with the control, the content of lutein increased by 46 % and the content of β-carotene increased by 77 % when the concentration of creatinine was 500 μg/mL. In conclusion, creatinine can effectively improve the production lutein and β-carotene in D. bardawil, which is more conducive under lower light intensity.