Effects of Sulfur, Iron and Manganese Starvation on Growth, β-carotene Production and Lipid Profile of Dunaliella salina

Abstract

Objective: Microalgal pharmaceutical biotechnology is mainly dependent on the biomass yield and also the final concentration of the obtained lipids. β-carotene is one of the most precious nutraceuticals, of both preventive and therapeutics importance in pharmacy and medicine. Dunaliella salina is known as famous β-carotene producer which could accumulate the β-carotene up to 10% of its dry cell weights. The amount of different macro and micronutrients in D. salina culture medium defines its productivity and β-carotene content. Methods: In this study, the effects of sulfur, iron and manganese deprivation, on cell growth and β-carotene biosynthesis in a naturally isolated strain of D. salina was examined. Besides, the fatty acid profile of the naturally isolated strain was also investigated. Results: Sulfur, iron and manganese deprivation caused a noticeable decrease in the cell growth of D. salina. On the other hand, in nutrient depleted media, the maximum β-carotene concentration was significantly improved (14.616 mg L-1 in sulfur starvation, 14.994 mg L-1 in iron starvation and 10.119 mg L-1 in manganese starvation media) compared with initial values (6.753 mg L-1) in basic culture medium. The obtained fatty acids from the studied microalgal strain found to be some important saturated, monounsaturated and polyunsaturated fatty acids. Conclusion: Owing to its significant growth rate, β-carotene contents and fatty acid profile; the naturally isolated microalgal strain could be exploited as a potential producer strain. Besides, the nutrient limitation strategy could be effectively employed to improve the β-carotene production procedure in D. salina. This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.

Production of β‐carotene with Dunaliella salina CCAP19/18 at physically simulated outdoor conditions

“…A maximum volumetric β‐carotene productivity of 2.9 mg L ‐1 d ‐1 was reached after 2.8 d. The overall volumetric productivity was estimated to be 1.7 mg L ‐1 d ‐1 . In literature, after applying stress phase of 10 days a comparable overall productivity of 1.7 mg L ‐1 d ‐1 was published with a maximum of 1.9 mg L ‐1 d ‐1 in shaked Erlenmeyer flasks [49]. Applying a column reactor, an overall volumetric β‐carotene productivity of 5 mg L ‐1 d ‐1 was shown [50].…”

“…Total carotenoid concentrations (including ß‐carotene, lutein, astaxanthin, lycopene) of 19–20 mg L ‐1 measured spectrometrically have already been reported applying open raceway pond cultivations at typical cell concentrations of 0.33‐1.2 g CDW L ‐1 D. salina (estimated content of 20 to 57 mg carotenoids g −1 dry cell weight) [26, 27]. An overall β‐carotene productivity of 1.7 mg L ‐1 d ‐1 with a maximum of 1.9 mg L ‐1 d ‐1 was published in shaked Erlenmeyer flasks [49]. Applying a column reactor an overall volumetric β‐carotene productivity of 5 mg L ‐1 d ‐1 was shown [50].…”

Carotenoids Overproduction in Dunaliella Sp.: Transcriptional Changes and New Insights through Lycopene β Cyclase Regulation

“…Many researchers reviewed and tried to pose the possible mechanism involved in its accumulation. In fact, carotenoid accumulation depends on the level and quality of light [8], temperature [22], nutrient availability as nitrogen [23,24], sulfur, iron, and manganese [25], phosphorus [26], salinity [27][28][29], etc. Stress conditions stimulate the production of reactive oxygen species (ROS), which could play the role of the second messenger for the expression of certain transcription factors, resulting in the accumulation of antioxidant molecules by cells [30].…”

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“…Identification of Dunaliella species/strains has already been the subject of morphological, physiological and molecular studies (Hexin et al, 2016;Kim, Ahn, Jeon, & Jin, 2017;Shaker, Morowvat, & Ghasemi, 2017). Internal Transcribed Spacer (ITS) regions have been frequently utilized for discrimination of genetic variation in green algae and to study the phylogeny and taxonomy of Dunaliella, as well as the ribulose-bisphosphate carboxylase (rbcL) gene (Coleman, Suarez, & Goff, 1994;González, Coleman, Gómez, & Montoya, 2001;Buchheim, Kirkwood, Buchheim, Verghese, & Henley, 2010).…”

“…β-carotene is one of the most precious nutraceuticals of both preventive and therapeutics importance in medicine and pharmacy. The pigment β-carotene is in high demand as an antioxidant and as a food coloring agent (Shaker et al, 2017). Other species belonging to the genus Dunaliella can also accumulate β-carotene as D. parva W. Lerche.…”