Enhancing carotenoid accumulation in Dunaliella bardawil by combined treatments with fulvic acid and optimized culture conditions.

Natural carotenoids from microalgae have received more attention as an alternative source. In this study, fulvic acid (FA), a plant growth regulator, was used to enhance carotenoid accumulation in microalgae Dunaliella bardawil rich in lutein. However, the addition of FA promoted pigment synthesis but also exhibited an inhibitory effect on biomass.

Enhancing astaxanthin accumulation through the expression of the plant-derived astaxanthin biosynthetic pathway in Dunaliella salina.

Dunaliella salina, a microalga that thrives under high-saline conditions, is notable for its high β-carotene content and the absence of a polysaccharide cell wall. These unique characteristics render it a prime candidate as a cellular platform for astaxanthin production. In this study, our initial tests in an E.

Involvement of Transcription Factors and Regulatory Proteins in the Regulation of Carotenoid Accumulation in Plants and Algae.

Carotenoids are essential for photosynthesis and photoprotection in photosynthetic organisms, which are widely used in food coloring, feed additives, nutraceuticals, cosmetics, and pharmaceuticals. Carotenoid biofortification in crop plants or algae has been considered as a sustainable strategy to improve human nutrition and health. However, the regulatory mechanisms of carotenoid accumulation are still not systematic and particularly scarce in algae.

DbMADS regulates carotenoid metabolism by repressing two carotenogenic genes in the green alga Dunaliella sp. FACHB-847.

MADS transcription factors are involved in the regulation of fruit development and carotenoid metabolism in plants. However, whether and how carotenoid accumulation is regulated by algal MADS are largely unknown. In this study, we first used functional complementation to confirm the functional activity of phytoene synthase from the lutein-rich Dunaliella sp.

Roles of Two Phytoene Synthases and Orange Protein in Carotenoid Metabolism of the β-Carotene-Accumulating .

Phytoene synthase (PSY) is a key enzyme in carotenoid metabolism and often regulated by orange protein. However, few studies have focused on the functional differentiation of the two PSYs and their regulation by protein interaction in the β-carotene-accumulating CCAP 19/18. In this study, we confirmed that DsPSY1 from possessed high PSY catalytic activity, whereas DsPSY2 almost had no activity.

Engineering the β-Carotene Metabolic Pathway of Microalgae To Confirm Its Carotenoid Synthesis Pattern in Comparison To Bacteria and Plants.

is the most salt-tolerant eukaryote and has the highest β-carotene content, but its carotenoid synthesis pathway is still unclear, especially the synthesis of lycopene, the upstream product of β-carotene. In this study, , , , , , , and genes were cloned from and expressed in Escherichia coli. A series of carotenoid engineering E.

Effects of Piperonyl Butoxide on the Accumulation of Lipid and the Transcript Levels of in .

As one of the sources of biodiesel, microalgae are expected to solve petroleum shortage. In this study, different concentrations of piperonyl butoxide were added to the culture medium to investigate their effects on the growth, pigment content, lipid accumulation, and content of carotenoids in . The results showed that piperonyl butoxide addition significantly decreased the biomass, chlorophyll content, and total carotenoid content but hugely increased the lipid accumulation.

A strategy to promote carotenoids production in Dunaliella bardawil by melatonin combined with photoinduction.

Microalgae are considered to be a very promising class of raw material for carotenoid production. In this study, melatonin (MLT), a widely used plant growth regulator, was added to the autotrophic medium of Dunaliella bardawil to explore its effects on the growth and pigment accumulation of Dunaliella bardawil. The results showed that the induction of exogenous MLT alone was not beneficial to the growth and pigment accumulation of Dunaliella bardawil, and the higher the concentration, the more obvious the inhibitory effect on the algal cells.

Two Triacylglycerol Lipases Are Negative Regulators of Chilling Stress Tolerance in Arabidopsis.

Cold stress is one of the abiotic stress conditions that severely limit plant growth and development and productivity. Triacylglycerol lipases are important metabolic enzymes for the catabolism of triacylglycerols and, therefore, play important roles in cellular activities including seed germination and early seedling establishment. However, whether they play a role in cold stress responses remains unknown.

DMDL 9010 alleviates dextran sodium sulfate (DSS)-induced colitis and behavioral disorders by facilitating microbiota-gut-brain axis balance.

Previous studies have found that probiotic supplements can ameliorate mental behavioral disorders. This study investigated the effects of DMDL 9010 (LP9010) intake on the depression-like behavior induced by dextran sodium sulfate (DSS) and its possible mechanism. Male C57BL/6N mice were fed with DSS to establish the model of ulcerative colitis.

The expression pattern of β-carotene ketolase gene restricts the accumulation of astaxanthin in Dunaliella under salt stress.

Dunaliella salina can accumulate a large amount of β-carotene which is generally considered to be its terminal product of carotenoid metabolism. In this study, it was proved that D. salina has the ketolase (DsBKT) of catalyzing the synthesis of astaxanthin, the downstream products of β-carotene.

Creatinine combined with light increases the contents of lutein and β-carotene, the main carotenoids of Dunaliella bardawil.

Dunaliella bardawil, a unicellular green alga, can accumulate a large amount of lutein and β-carotene under stresses. Using chemical inducers combined with abiotic stress to promote the accumulation of high value-added products such as lipids and carotenoids in microalgae has attracted more and more attention. In this study, creatinine was added into autotrophic medium to investigate its effects on the growth, chlorophyll content, and the ingredients and content of carotenoids in D.

Regulation of carotenoid degradation and production of apocarotenoids in natural and engineered organisms.

Carotenoids are important precursors of a wide range of apocarotenoids with their functions including: hormones, pigments, retinoids, volatiles, and signals, which can be used in the food, flavors, fragrances, cosmetics, and pharmaceutical industries. This article focuses on the formation of these multifaceted apocarotenoids and their diverse biological roles in all living systems. Carotenoid degradation pathways include: enzymatic oxidation by specific carotenoid cleavage oxygenases (CCOs) or nonspecific enzymes such as lipoxygenases and peroxidases and non-enzymatic oxidation by reactive oxygen species.

Structural characterization of a novel Fr. polysaccharide and its immunity activity in BALB/c mice.

Fr. has been regarded as a great edible medicinal fungal resource in China. In this study, Fr.

Functional Identification of Two Types of Carotene Hydroxylases from the Green Alga Rich in Lutein.

The salt-tolerant unicellular alga FACHB-847 can accumulate large amounts of lutein, but the underlying cause of massive accumulation of lutein is still unknown. In this study, genes encoding two types of carotene hydroxylases, , β-carotene hydroxylase (DbBCH) and cytochrome P450 carotenoid hydroxylase (DbCYP97s; DbCYP97A, DbCYP97B, and DbCYP97C), were cloned from . Their substrate specificities and enzyme activities were tested through functional complementation assays in .

Transcriptomic insights into the heat stress response of Dunaliella bardawil.

The halophilic green alga Dunaliella bardawil has been used for commercial production of natural β-carotene by large-scale outdoor cultivation, which often suffers from heat stress especially at noon in hot summers. In this study, the effects of heat stress on cell growth, pigment contents, and activities of antioxidant system in D. bardawil were studied, and RNA-seq experiment was conducted to analyze the transcriptional response to heat stress (42 °C for 2 h) in D.

Transgenic microalgae as bioreactors.

Microalgae are unicellular organisms that act as the crucial primary producers all over the world, typically found in marine and freshwater environments. Most of them can live photo-autotrophically, reproduce rapidly, and accumulate biomass in a short period efficiently. To adapt to the uninterrupted change of the environment, they evolve and differentiate continuously.

The bifunctional identification of both lycopene β- and ε-cyclases from the lutein-rich Dunaliella bardawil.

The halophilic green alga Dunaliella bardawil FACHB-847 is rich in lutein and α-carotene, which has great potential for carotenoid production in open ponds. In this study, genes encoding lycopene β- and ε-cyclases (DbLcyB and DbLcyE) from D. bardawil FACHB-847 were functionally identified by genetic complementation in E.

Effects of triethylamine on the expression patterns of two G3PDHs and lipid accumulation in Dunaliella tertiolecta.

Glycerol-3-phosphate (G3P) is the important precursors for triacylglycerol synthesis, while glycerol-3-phosphate dehydrogenase (GPDH) determines the formation of G3P. In this study, two GDPH genes, Dtgdp1 and Dtgdp2 were isolated and identified from Dunaliella tertiolecta. The full-length Dtgdp1 and Dtgdp2 CDS were 2016 bp and 2094 bp, which encoded two putative protein sequences of 671 and 697 amino acids with predicted molecular weights of 73.

Sodium azide intervention, salinity stress and two-step cultivation of Dunaliella tertiolecta for lipid accumulation.

A two-step strategy was employed to culture Dunaliella tertiolecta, an oleaginous unicellular green alga, combined by the salt stress and sodium azide intervention, to observe their effects on its lipid accumulation. When the algae cultured at different salt concentrations reached the logarithmic growth phase, sodium azide was added. The results showed that the addition of sodium azide significantly increased the lipid content and had no significant effect on cell biomass.

Two-Stage Cultivation of Dunaliella tertiolecta with Glycerol and Triethylamine for Lipid Accumulation: a Viable Way To Alleviate the Inhibitory Effect of Triethylamine on Biomass.

Microalgae are promising alternatives for sustainable biodiesel production. Previously, it was found that 100 ppm triethylamine greatly enhanced lipid production and lipid content per cell of by 20% and 80%, respectively. However, triethylamine notably reduced biomass production and pigment contents.

High-value bioproducts from microalgae: Strategies and progress.

Microalgae have been considered as alternative sustainable resources for high-value bioproducts such as lipids (especially triacylglycerides [TAGs]), polyunsaturated fatty acids (PUFAs), and carotenoids, due to their relatively high photosynthetic efficiency, no arable land requirement, and ease of scale-up. It is of great significance to exploit microalgae for the production of high-value bioproducts. How to improve the content or productivity of specific bioproducts has become one of the most urgent challenges.

Carotenoids biosynthesis and cleavage related genes from bacteria to plants.

Carotenoids are essential for photosynthesis and photoprotection in photosynthetic organisms and beneficial for human health. Apocarotenoids derived from carotenoid degradation can serve critical functions including hormones, volatiles, and signals. They have been used commercially as food colorants, animal feed supplements, and nutraceuticals for cosmetic and pharmaceutical purposes.