Metabolic responses and β-carotene production by the unicellular green alga Dunaliella salina exposed to leaf extracts

Abstract

Th e present work investigated the eff ects of aqueous extracts of eucalyptus (Eucalyptus globulus) and elderberry (Sambucus ebulus) leaves on β-carotene productivity in Dunaliella salina, a green microalga. Leaf extracts from eucalyptus have greater amounts of phenolics and fl avonoids, as well as greater ferric reducing antioxidant potential than elderberry. Th e extracts of both species greatly inhibited growth of algal suspensions. However, chlorophyll and β-carotene concentration increased in cells treated with leaf extracts, and the highest values were detected in 1 % eucalyptus and 2 % elderberry extracts. Fresh weight, total sugar, and protein content signifi cantly increased following exposure of cells to diff erent doses of leaf extracts. However, in doses containing more than 2 % eucalyptus, the upward trend for total sugar and protein ceased and remained statistically unchanged. Th ese results suggest that metabolic modifi cations enable D. salina cells to tolerate the stress induced by the leaf extracts through allocating carbon fl ux to the synthesis of osmolytes and putative antioxidant molecules (e.g. sugars and β-carotene). Th erefore, the use of leaf extracts holds potential to be a promising and eff ective way to improve D. salina cultivation for β-carotene production and other biotechnological and industrial applications.

Algal cell response to laboratory-induced cadmium stress: a multimethod approach

“…It is well known that the response of green algal cells under heavy metal stress includes the allocation of carbon flux to the synthesis of osmolytes and putative antioxidant molecules (e.g. sugars and β-carotene) (Einali et al 2017). The amount of chlorophyll also varies under such conditions (Nikookar et al 2005;Saha et al 2018).…”

Trascriptome meta-analysis of microalga Dunaliella tertiolecta under stress condition

“…The microalga Dunaliella is frequently considered for industrial applications because of its potential to produce high value compounds such as beta-carotene, its high growth rate, tolerance under extreme physiological conditions, lack of cell wall, and low energy requirements in harvesting (Einali et al 2017, Oren 2010, Rammuni et al 2019).…”

Effects of different culture media on physiological features and laboratory scale production cost of Dunaliella salina

“…Some studies have addressed significant effects of light and adaptive evolution [ 8 ], temperature [ 9 ] and gene expression responses to stress [ 10 ] on pigment accumulation from D. salina cells. In addition to cultivation features, strategies to enhance carotenoid biosynthesis using leaf extracts was described by Einali and colleagues (2017) [ 11 ]. However, few studies have demonstrated the correlation of microalgal biomass cultivated under common media [ 6 , 7 , 12 ], pigment profile and laboratory cost in D. salina cultivation (no stress applied).…”