A Comparison of β-Carotene, Phytoene and Amino Acids Production in Dunaliella salina DF 15 (CCAP 19/41) and Dunaliella salina CCAP 19/30 Using Different Light Wavelengths

Strains of Dunaliella salina microalgae are of considerable research and industrial interest because they hyper-accumulate beta-carotene as well as produce high-quality protein. To explore the co-production of valuable compounds in D. salina, this study compared the production of beta-carotene, phytoene and amino acids in two strains cultivated under white, red or blue light until no further nitrogen was available. D. salina DF15 (CCAP 19/41 (PLY DF15)) produced more than 12% beta-carotene (ash-free dry weight (AFDW) basis), and red light triggered the production of 9-cis beta-carotene at a 9-cis/all-trans beta-carotene ratio of 1.5. Phytoene production was also evident in D. salina DF15 under all conditions, particularly under blue light. However, the profile of essential amino acids (EAAs) and calculation of the essential amino acid index (EAAI) was less than ideal in terms of protein quality, for both strains. Umami compounds, quantified as monosodium glutamate (MSG) equivalents, indicated a higher equivalent umami concentration (EUC) in D. salina DF15 under red light (3.2 g MSG/100 g AFDW) than in D. salina CCAP19/30. Overall, D. salina DF15 demonstrates valuable traits for further exploration and product optimisation.

Automated summary

Strains of Dunaliella salina microalgae are of interest due to their ability to accumulate beta-carotene and produce high-quality protein. However, the protein quality in terms of essential amino acids could be improved, and the strain demonstrates a higher umami compound concentration under red light.