Effects of salinity increase on carotenoid accumulation in the green alga Dunaliella salina

Borowitzka, Michael A.; Borowitzka, L. J.; Kessly, David Stuart

doi:10.1007/bf00023372

Cited by 138 publications

(68 citation statements)

References 23 publications

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“…The manifold strategies of halophile microbes to handle highly saline environments, and the fact that halophilicity occurs throughout the tree of life, suggests that adaptation to high salinity is, from the metabolic point of view, a rather trivial task. Changing pigment patterns in microalgae, which, besides illumination conditions, also is determined by the salinity, is regarded a prime example of the adaptive response to changing environmental conditions [40]. In the case of halophile PHA producers, Soto and colleagues reveled the role of PHA as chaperons, preventing protein agglomeration under combined stress exerted by salt and temperature, by investigating Pseudomonas sp.…”

Section: Discussionmentioning

confidence: 99%

Production of Polyhydroxyalkanoate (PHA) Biopolyesters by Extremophiles?

Koller¹

2017

MOJPS

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The article reviews the current state of knowledge of the production of polyhydroxyalkanoate (PHA) biopolyesters under extreme environmental conditions.Although PHA production by extremophiles is not realized yet at industrial scale, significant PHA accumulation under high salinity or extreme pH-or temperature conditions was reported for diverse representatives of the microbial domains of both Archaea and Bacteria. Several mechanisms were proposed to explain the mechanistic role of PHA and their monomers as microbial cell-and enzyme protective chaperons and the factors boosting PHA biosynthesis under environmental stress conditions. The potential of selected extremophile strains, isolated from extreme environments like glaciers, hot springs, saline brines, or from habitats highly polluted with heavy metals or solvents, for efficient future PHA production on an industrially relevant scale is assessed based on the basic data available in the scientific literature. The article reveals that, beside the needed optimization of other cost-decisive factors like inexpensive raw materials or efficient downstream processing, the application of extremophile production strains can drastically safe energy costs, are easily accessible towards long-term cultivation in chemostat processes, and therefore might pave the way towards cost-efficient PHA production, even combined with safe disposal of industrial waste streams. However, further challenges have still to be overcome in terms of strain improvement and process engineering aspects.

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Section: Discussionmentioning

confidence: 99%

Production of Polyhydroxyalkanoate (PHA) Biopolyesters by Extremophiles?

Koller¹

2017

MOJPS

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“…Diversos estudios han demostrado que la producción de carotenoides en D. salina puede optimizarse mediante variaciones de las condiciones de cultivo, las cuales incluyen aumento de la salinidad, intensidad luminosa, temperatura (Ben-Amotz 1987, Gómez et al 2003 y/o limitación de nutrientes (Borowitzka y Borowitzka 1988, Borowitzka et al 1990, Mendoza et al 1999.…”

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Carotenogénesis de cinco cepas del alga <i>Dunaliella</i> sp. (Chlorophyceae) aisladas de lagunas hipersalinas de Venezuela

Guevara¹,

Lodeiros²,

Gómez

et al. 2014

RBT

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Carotenogenesis of five strains of the algae Dunaliella sp. (Chlorophyceae) isolated from Venezuelan hypersaline lagoons. We evaluated discontinuous cultures (Algal medium at 0.5 mM of NaNO 3 , and 27% NaCl) of five strains of Dunaliella sp. isolated from Venezuelan hypersaline lagoons (Araya, Coche, Peonía, Cumaraguas, and Boca Chica) and one strain from a reference collection (Dunaliella salina, LB1644). Cultures were maintained to 25±1 °C, with constant aeration, photoperiod 12:12, and two light intensities (195 and 390 µE.m -2 .s -1 ) during 30 days. Cell count was recorded on a daily basis using a Neubaüer camera. Totals of chlorophyll a and carotenoids were measured at the end of the experiment. The largest cellular densities were measured during the smallest light intensities. The strain with the largest cellular density was isolated from Boca Chica (8 x10 6 and 2.5 x10 6 cel.ml -1 a 390 and 195µE.m -2 .s -1 , respectively). The increment of light intensity produced a significant reduction of growth rates in all strains. Totals of carotenoids by volume were as large as 390 µE.m -2 .s -1 . Strains LB1644, from Coche and Araya were those that produced the largest amount of carotenoids (38.4; 32.8 and 21.0 µg.ml -1 , respectively). Differences total carotenoids by cell between treatments were significant. The largest concentration was 390 µE.m -2 .s -1 . The strains LB1644 and Coche produced the highest values of carotenes (137.14 and 106.06 pg.cel -1 , respectively). Differences in the relation carotenoid:chlorophyll a between the strains at various light intensities was significant. Strains LB1644 presented the largest value of the relation carotenoids:chlorophyll a (20:1) at 195 µE.m -2 .s -1 . No significant differences were detected in the strain Coche (15:1). All the other strains showed relations lower than one. Our results suggest that the strains of Coche and Araya show potential to be used in the biotechnology of carotenoids production. Rev. Biol. Trop. 53(3-4): 331-337. Epub 2005 Oct 3.

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“…Among the conditions that induce accumulation of carotenoids are high photon flux densities (wavelength range, 400-700 nm). Such inductive conditions have been reported to result in increases of β-carotene levels from 1% dry weight (dw) to 10% dw (2,12,13).…”

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confidence: 99%

“…β-Carotene occurs as a number of isomers, two of which, 9-cis and all-trans, make up approximately 80% of the total β-carotene in the microalgae Dunaliella bardawil (9,11,12). UV radiations have been shown to have both positive and negative effects on the viability of microalgae cultures (14), and some of the commercially attractive carotenoids produced by D. bardawil have absorption in the UV-A spectrum (15).…”

mentioning

confidence: 99%

β-Carotene production enhancement by UV-A radiation in Dunaliella bardawil cultivated in laboratory reactors

Mogedas¹,

Casal

Forján

et al. 2009

Journal of Bioscience and Bioengineering

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β-carotene is an antioxidant molecule of commercial value that can be naturally produced by certain microalgae that mostly belong to the genus Dunaliella. So far, nitrogen starvation has been the most efficient condition for enhancing β-carotene accumulation in Dunaliella. However, while nitrogen starvation promotes β-carotene accumulation, the cells become non-viable; consequently under such conditions, continuous β-carotene production is limited to less than 1 week. In this study, the use of UV-A radiation as a tool to enhance long-term β-carotene production in Dunaliella bardawil cultures was investigated. The effect of UV-A radiation (320-400 nm) added to photosynthetically active radiation (PAR, 400-700 nm) on growth and carotenoid accumulation of D. bardawil in a laboratory air-fluidized bed photobioreactor was studied. The results were compared with those from D. bardawil control cultures incubated with PAR only. The addition of 8.7 W . m − 2 UV-A radiation to 250 W . m − 2 PAR stimulated long-term growth of D. bardawil. Throughout the exponential growth period the UV-A irradiated cultures showed enhanced carotenoid accumulation, mostly as β-carotene. After 24 days, the concentration of β-carotene in UV-A irradiated cultures was approximately two times that of control cultures. Analysis revealed that UV-A clearly induced major accumulation of all-trans β-carotene. In N-starved culture media, β-carotene biosynthesis in UV-A irradiated cultures was stimulated. We conclude that the addition of UV-A to PAR enhances carotenoid production processes, specifically all-trans β-carotene, in D. bardawil cells without negative effects on cell growth.

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Effects of salinity increase on carotenoid accumulation in the green alga Dunaliella salina

Cited by 138 publications

References 23 publications

Production of Polyhydroxyalkanoate (PHA) Biopolyesters by Extremophiles?

Production of Polyhydroxyalkanoate (PHA) Biopolyesters by Extremophiles?

Carotenogénesis de cinco cepas del alga <i>Dunaliella</i> sp. (Chlorophyceae) aisladas de lagunas hipersalinas de Venezuela

β-Carotene production enhancement by UV-A radiation in Dunaliella bardawil cultivated in laboratory reactors

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