Induction of Carotenoid Accumulation by Salt Stress in a Newly Isolated Dysmorphococcus Strain from Antalya, Türkiye

Microalgae are some of the organisms that produce carotenoids, which are high value metabolites. However, algae produce carotenoids under stress conditions and there is a need for more practical and economical ways to increase carotenoid accumulation in algae. Haematococcus lacustris has been one of the most important species for the production of industrial-scale carotenoids in biotechnology. In recent years, new algal species have been shown to accumulate carotenoids as alternative resources of carotenoids; Dysmorphococcus globosus is one of them. In a previous study, we isolated and identified for the first time a D. globosus strain in Türkiye. In the current study, we tested different stress conditions on carotenoid accumulation on D. globosus-KINIK and a Haematococcus sp.-KINIK strain that was isolated along with it from the same water sample. We partially sequenced the 18S rRNA gene of the newly isolated Haematoccoccus strain; it is 96% identical to Haematococcus lacustris. Further studies are necessary to determine the species of our strain. We tested three stress conditions: (i) salt stress by adding 2 g L−1 NaCl, (ii) fresh water stress by replacing growth media with fresh water, and iii) sea water stress by replacing growth media with sea water. Salt stress and fresh water stress have been shown to increase carotenoids in Haematococcus strains in the literature; our Haematococcus strain also responded well to these stresses and accumulated carotenoids. To our knowledge, none of these stresses have been tested for Dysmosphococcus strains in the literature. Our results show that D. globosus-KINIK also accumulates carotenoids under salt stress and fresh water, with salt stress being more effective. We also tested different growth media on the growth of D. globosus-KINIK and showed that it can grow without vitamin supplementation. Our study reveals local strains of carotenogenic algae in Türkiye for consideration for industrial-scale carotenoid production.